Scholars@Duke
Volker Blum

Volker Blum

Rooney Family Associate Professor of Mechanical Engineering and Materials Science
Thomas Lord Department of Mechanical Engineering and Materials Science

Selected Publications

Roadmap on methods and software for electronic structure based simulations in chemistry and materials

Journal Article Electronic Structure · December 1, 2024 This Roadmap article provides a succinct, comprehensive overview of the state of electronic structure (ES) methods and software for molecular and materials simulations. Seventeen distinct sections collect insights by 51 leading scientists in the field. Eac ... Full text Cite

Site Disorder Drives Cyanide Dynamics and Fast Ion Transport in Li<sub>6</sub>PS<sub>5</sub>CN.

Journal Article Chemistry of materials : a publication of the American Chemical Society · October 2024 Halide argyrodite solid-state electrolytes of the general formula Li6PS5X exhibit complex static and dynamic disorder that plays a crucial role in ion transport processes. Here, we unravel the rich interplay between site disor ... Full text Cite

Roadmap on data-centric materials science

Journal Article Modelling and Simulation in Materials Science and Engineering · September 1, 2024 Science is and always has been based on data, but the terms ‘data-centric’ and the ‘4th paradigm’ of materials research indicate a radical change in how information is retrieved, handled and research is performed. It signifies a transformative shift toward ... Full text Cite

Hydrogen Bonding Analysis of Structural Transition-Induced Symmetry Breaking and Spin Splitting in a Hybrid Perovskite Employing a Synergistic Diffraction-DFT Approach.

Journal Article Journal of the American Chemical Society · August 2024 Two-dimensional (2D) hybrid organic-inorganic perovskites (HOIPs) offer an outstanding opportunity for spin-related technologies owing in part to their tunable structural symmetry breaking and distortions driven by organic-inorganic hydrogen (H) bonds. How ... Full text Cite

Homochiral and Heterochiral Cation Mixing in 2D Perovskites for Enhanced Structural Asymmetry and Spin Splitting

Journal Article ACS Materials Letters · July 1, 2024 Overcoming the constraints of single-cation phases and further enhancing structural asymmetry represent critical objectives for optimizing emergent optoelectronic and spin-related properties in two-dimensional (2D) hybrid organic-inorganic perovskites (HOI ... Full text Cite

Efficient all-electron hybrid density functionals for atomistic simulations beyond 10 000 atoms.

Journal Article The Journal of chemical physics · July 2024 Hybrid density functional approximations (DFAs) offer compelling accuracy for ab initio electronic-structure simulations of molecules, nanosystems, and bulk materials, addressing some deficiencies of computationally cheaper, frequently used semilocal DFAs. ... Full text Cite

Molecular NMR shieldings, J-couplings, and magnetizabilities from numeric atom-centered orbital based density-functional calculations

Journal Article Electronic Structure · June 1, 2024 This paper reports and benchmarks a new implementation of nuclear magnetic resonance shieldings, magnetizabilities, and J-couplings for molecules within semilocal density functional theory, based on numeric atom-centered orbital (NAO) basis sets. NAO basis ... Full text Cite

Exploration, Prediction, and Experimental Verification of Structure and Optoelectronic Properties in I2-Eu-IV-X4 (I = Li, Cu, Ag; IV = Si, Ge, Sn; X = S, Se) Chalcogenide Semiconductors

Journal Article Chemistry of Materials · January 9, 2024 Recently, there has been extensive research into photovoltaic, thermoelectric, and nonlinear optical applications of chalcogenide semiconductors within the large set of defect-resistant I2-II-IV-X4 (I = Li, Cu, Ag; II = Ba, Sr, Eu, Pb; IV = Si, Ge, Sn; X = ... Full text Cite

Benchmark thermodynamic analysis of methylammonium lead iodide decomposition from first principles

Journal Article JPhys Energy · January 1, 2024 Hybrid organic-inorganic perovskites (HOIPs) such as methylammonium lead iodide (MAPbI3) are promising candidates for use in photovoltaic cells and other semiconductor applications, but their limited chemical stability poses obstacles to their widespread u ... Full text Cite

Thickness control of organic semiconductor-incorporated perovskites.

Journal Article Nature chemistry · December 2023 Two-dimensional organic semiconductor-incorporated perovskites are a promising family of hybrid materials for optoelectronic applications, owing in part to their inherent quantum well architecture. Tuning their structures and properties for specific proper ... Full text Cite

First-Principles Approach for Coupled Quantum Dynamics of Electrons and Protons in Heterogeneous Systems.

Journal Article Physical review letters · December 2023 The coupled quantum dynamics of electrons and protons is ubiquitous in many dynamical processes involving light-matter interaction, such as solar energy conversion in chemical systems and photosynthesis. A first-principles description of such nuclear-elect ... Full text Cite

Impact of Chiral Symmetry Breaking on Spin-Texture and Lone Pair Expression in Chiral Crystals of Hybrid Antimony and Bismuth Halides

Journal Article Chemistry of Materials · November 14, 2023 Chiral organic building blocks can be incorporated into hybrid organic-inorganic metal-halide crystalline semiconductors so as to control and impact the interconversion between light, charge, and spin. Here, we report a series of hybrid antimony and bismut ... Full text Cite

Curated materials data of hybrid perovskites: approaches and potential usage

Journal Article Trends in Chemistry · October 1, 2023 Over the past decade, hybrid perovskite research has evolved to a point where the literature contains an enormous volume of chemical and physical information. However, many essential material design challenges remain open for researchers to address. The di ... Full text Cite

Roadmap on electronic structure codes in the exascale era

Journal Article Modelling and Simulation in Materials Science and Engineering · September 1, 2023 Electronic structure calculations have been instrumental in providing many important insights into a range of physical and chemical properties of various molecular and solid-state systems. Their importance to various fields, including materials science, ch ... Full text Cite

Chiral Cation Doping for Modulating Structural Symmetry of 2D Perovskites.

Journal Article J Am Chem Soc · August 16, 2023 Cation mixing in two-dimensional (2D) hybrid organic-inorganic perovskite (HOIP) structures represents an important degree of freedom for modifying organic templating effects and tailoring inorganic structures. However, the limited number of known cation-m ... Full text Open Access Link to item Cite

Structure and electronic tunability of acene alkylamine based layered hybrid organic-inorganic perovskites from first principles

Journal Article Physical Review Materials · August 1, 2023 Twelve layered hybrid organic-inorganic perovskites combining oligoacene derivatives [phenylmethylammonium (PMA), naphthylmethylammonium (NMA), anthrylmethylammonium (AMA), and tetrylmethylammonium (TMA)] and lead halides (Cl-, Br-, and I- anions) are inve ... Full text Cite

Chiral Perovskite Nanoplatelets with Tunable Circularly Polarized Luminescence in the Strong Confinement Regime

Journal Article Advanced Optical Materials · June 19, 2023 Chiral perovskite nanocrystals have emerged as an interesting chiral excitonic platform that combines both structural flexibility and superior optoelectronic properties. Despite several recent demonstrations of optical activity in various chiral perovskite ... Full text Cite

Coherent Phonon-Induced Modulation of Charge Transfer in 2D Hybrid Perovskites

Journal Article Advanced Functional Materials · May 17, 2023 Electron–phonon interactions play an essential role in charge transport and transfer processes in semiconductors. For most structures, tailoring electron–phonon interactions for specific functionality remains elusive. Here, it is shown that, in hybrid pero ... Full text Cite

Phonon and Raman caculation data from: Coherent Phonon‐Induced Modulation of Charge Transfer in 2D Hybrid Perovskites

Dataset · March 8, 2023 Electron-phonon interactions play an essential role in charge transport and transfer processes in semiconductors. For most structures, tailoring electron-phonon interactions for specific functionality remains elusive. Here, we show that, in hybrid perovski ... Full text Cite

Data from: Chiral perovskite nanoplatelets with tunable circularly polarized luminescence in the strong confinement regime

Dataset · February 28, 2023 Chiral perovskite nanocrystals have emerged as an interesting chiral excitonic platform that combines both structural flexibility and superior optoelectronic properties. Despite several recent demonstrations of optical activity in various chiral perovskite ... Full text Cite

Metal Halide Perovskite Heterostructures: Blocking Anion Diffusion with Single-Layer Graphene.

Journal Article Journal of the American Chemical Society · February 2023 The development of metal halide perovskite/perovskite heterostructures is hindered by rapid interfacial halide diffusion leading to mixed alloys rather than sharp interfaces. To circumvent this outcome, we developed an ion-blocking layer consisting of sing ... Full text Cite

Phase Stability, Band Gap Tuning, and Rashba Splitting in Selenium-Alloyed Bournonite: CuPbSb(S1−xSex)3

Journal Article Chemistry of Materials · January 24, 2023 Recently, bournonite (CuPbSbS3) has been identified as a potential ferroelectric photovoltaic (PV) material with a 1.3 eV band gap, which falls in an appropriate range for single-junction PV devices. Progress in applying bournonite has yielded several stud ... Full text Cite

Large Scale Quantum Chemistry with Tensor Processing Units.

Journal Article Journal of chemical theory and computation · January 2023 We demonstrate the use of Googles cloud-based Tensor Processing Units (TPUs) to accelerate and scale up conventional (cubic-scaling) density functional theory (DFT) calculations. Utilizing 512 TPU cores, we accomplish the largest such DFT computation to da ... Full text Cite

Exact constraints and appropriate norms in machine-learned exchange-correlation functionals.

Journal Article The Journal of chemical physics · November 2022 Machine learning techniques have received growing attention as an alternative strategy for developing general-purpose density functional approximations, augmenting the historically successful approach of human-designed functionals derived to obey mathemati ... Full text Cite

Localized Resolution of Identity Approach to the Analytical Gradients of Random-Phase Approximation Ground-State Energy: Algorithm and Benchmarks.

Journal Article Journal of chemical theory and computation · September 2022 We develop and implement a formalism which enables calculating the analytical gradients of particle-hole random-phase approximation (RPA) ground-state energy with respect to the atomic positions within the atomic orbital basis set framework. Our approach i ... Full text Cite

Kinetically Controlled Structural Transitions in Layered Halide-Based Perovskites: An Approach to Modulate Spin Splitting.

Journal Article Journal of the American Chemical Society · August 2022 Two-dimensional hybrid organic-inorganic perovskite (HOIP) semiconductors with pronounced spin splitting, mediated by strong spin-orbit coupling and inversion symmetry breaking, offer the potential for spin manipulation in future spintronic applications. H ... Full text Cite

The Structural Origin of Chiroptical Properties in Perovskite Nanocrystals with Chiral Organic Ligands

Journal Article Advanced Functional Materials · June 1, 2022 The authors investigate how chiral ligands attached to perovskite nanocrystal (PNC) surfaces structurally distort the perovskite lattice. Chiral electro-optical properties of the resulting PNCs are demonstrated through the fabrication of a circularly polar ... Full text Cite

Boron nitride on SiC(0001)

Journal Article Physical Review Materials · June 1, 2022 In the field of van der Waals heterostructures, the twist angle between stacked two-dimensional layers has been identified to be of utmost importance for the properties of the heterostructures. In this context, we previously reported the growth of a single ... Full text Cite

Nuclear-electronic orbital approach to quantization of protons in periodic electronic structure calculations.

Journal Article The Journal of chemical physics · June 2022 The nuclear-electronic orbital (NEO) method is a well-established approach for treating nuclei quantum mechanically in molecular systems beyond the usual Born-Oppenheimer approximation. In this work, we present a strategy to implement the NEO method for pe ... Full text Cite

Influence of Annealing and Composition on the Crystal Structure of Mixed-Halide, Ruddlesden-Popper Perovskites

Journal Article Chemistry of Materials · April 12, 2022 Mixed-halide two-dimensional (2D) hybrid organic-inorganic perovskites offer an important opportunity to control the band gap for applications in optoelectronic devices. This study focuses on phenethylammonium lead halide [(PEA)2Pb(I1-xBrx)4] films, the pu ... Full text Cite

All-Electron BSE@GW Method for K-Edge Core Electron Excitation Energies.

Journal Article Journal of chemical theory and computation · March 2022 We present an accurate computational approach to calculate absolute K-edge core electron excitation energies as measured by X-ray absorption spectroscopy. Our approach employs an all-electron Bethe-Salpeter equation (BSE) formalism based on GW Full text Cite

Cubic Crystal Structure Formation and Optical Properties within the Ag-BII-MIV-X (BII = Sr, Pb; MIV = Si, Ge, Sn; X = S, Se) Family of Semiconductors.

Journal Article Inorganic chemistry · February 2022 Quaternary chalcogenide semiconductors are promising materials for energy conversion and nonlinear optical applications, with properties tunable primarily by varying the elemental composition and crystal structure. Here, we first analyze the connections am ... Full text Cite

On the optical anisotropy in 2D metal-halide perovskites.

Journal Article Nanoscale · January 2022 Two-dimensional metal-halide perovskites (MHPs) are versatile solution-processed organic/inorganic quantum wells where the structural anisotropy creates profound anisotropy in their electronic and excitonic properties and associated optical constants. We h ... Full text Cite

Density Functional Theory Study of Reaction Equilibria in Signal Amplification by Reversible Exchange.

Journal Article Chemphyschem : a European journal of chemical physics and physical chemistry · October 2021 An in-depth theoretical analysis of key chemical equilibria in Signal Amplification by Reversible Exchange (SABRE) is provided, employing density functional theory calculations to characterize the likely reaction network. For all reactions in the network, ... Full text Cite

Density Functional Theory Study of Reaction Equilibria in Signal Amplification by Reversible Exchange.

Journal Article Chemphyschem : a European journal of chemical physics and physical chemistry · October 2021 The front cover artwork is provided by the groups of Prof. Thomas Theis (North Carolina State University) Prof. Volker Blum (Duke University). The image shows the reaction network of Signal Amplification by Reversible Exchange (SABRE), elucidated by densit ... Full text Cite

All-electron real-time and imaginary-time time-dependent density functional theory within a numeric atom-centered basis function framework.

Journal Article The Journal of chemical physics · October 2021 Real-time time-dependent density functional theory (RT-TDDFT) is an attractive tool to model quantum dynamics by real-time propagation without the linear response approximation. Sharing the same technical framework of RT-TDDFT, imaginary-time time-dependen ... Full text Cite

Structural, Optical, and Electronic Properties of Two Quaternary Chalcogenide Semiconductors: Ag2SrSiS4 and Ag2SrGeS4.

Journal Article Inorganic chemistry · August 2021 Quaternary chalcogenide materials have long been a source of semiconductors for optoelectronic applications. Recent studies on I2-II-IV-X4 (I = Ag, Cu, Li; II = Ba, Sr, Eu, Pb; IV = Si, Ge, Sn; X = S, Se) materials have shown particul ... Full text Cite

Structural descriptor for enhanced spin-splitting in 2D hybrid perovskites.

Journal Article Nature communications · August 2021 Two-dimensional (2D) hybrid metal halide perovskites have emerged as outstanding optoelectronic materials and are potential hosts of Rashba/Dresselhaus spin-splitting for spin-selective transport and spin-orbitronics. However, a quantitative microscopic un ... Full text Cite

Charge transfer states and carrier generation in 1D organolead iodide semiconductors

Journal Article Journal of Materials Chemistry A · July 14, 2021 Excited-state interactions between organic and inorganic components in hybrid metal halide semiconductors open up the possibility of moving charge and energy in deliberate ways, including energy funneling, triplet energy harvesting, or long-lived charge se ... Full text Cite

Quasi-four-component method with numeric atom-centered orbitals for relativistic density functional simulations of molecules and solids

Journal Article Physical Review B · June 15, 2021 We describe and benchmark the quasi-four-component (Q4C) approach to relativistic density functional simulations of molecules and solids, using precise, numerically tabulated atom-centered orbital (NAO) basis sets to discretize Dirac's equation. The Q4C ap ... Full text Cite

Accurate frozen core approximation for all-electron density-functional theory.

Journal Article The Journal of chemical physics · June 2021 We implement and benchmark the frozen core approximation, a technique commonly adopted in electronic structure theory to reduce the computational cost by means of mathematically fixing the chemically inactive core electron states. The accuracy and efficien ... Full text Cite

GPU-acceleration of the ELPA2 distributed eigensolver for dense symmetric and hermitian eigenproblems

Journal Article Computer Physics Communications · May 1, 2021 The solution of eigenproblems is often a key computational bottleneck that limits the tractable system size of numerical algorithms, among them electronic structure theory in chemistry and in condensed matter physics. Large eigenproblems can easily exceed ... Full text Cite

Mechanism of Additive-Assisted Room-Temperature Processing of Metal Halide Perovskite Thin Films.

Journal Article ACS applied materials & interfaces · March 2021 Perovskite solar cells have received substantial attention due to their potential for low-cost photovoltaic devices on flexible or rigid substrates. Thiocyanate (SCN)-containing additives, such as MASCN (MA = methylammonium), have been shown to control per ... Full text Cite

GIMS: Graphical Interface for Materials Simulations

Journal Article Journal of Open Source Software · January 7, 2021 Full text Cite

All-electron periodic G0W0 implementation with numerical atomic orbital basis functions: Algorithm and benchmarks

Journal Article Physical Review Materials · January 1, 2021 We present an all-electron, periodic G0W0 implementation within the numerical atomic orbital (NAO) basis framework. A localized variant of the resolution-of-the-identity (RI) approximation is employed to significantly reduce the computational cost of evalu ... Full text Cite

Trapping lead in perovskite solar modules with abundant and low-cost cation-exchange resins

Journal Article Nature Energy · December 1, 2020 One major concern for the commercialization of perovskite photovoltaic technology is the toxicity of lead from the water-soluble lead halide perovskites that can contaminate the environment. Here, we report an abundant, low-cost and chemically robust catio ... Full text Cite

ELSI — An open infrastructure for electronic structure solvers

Journal Article Computer Physics Communications · November 1, 2020 Routine applications of electronic structure theory to molecules and periodic systems need to compute the electron density from given Hamiltonian and, in case of non-orthogonal basis sets, overlap matrices. System sizes can range from few to thousands or, ... Full text Cite

GPU acceleration of all-electron electronic structure theory using localized numeric atom-centered basis functions

Journal Article Computer Physics Communications · September 1, 2020 We present an implementation of all-electron density-functional theory for massively parallel GPU-based platforms, using localized atom-centered basis functions and real-space integration grids. Special attention is paid to domain decomposition of the prob ... Full text Cite

Relativistic correction scheme for core-level binding energies from GW.

Journal Article The Journal of chemical physics · September 2020 We present a relativistic correction scheme to improve the accuracy of 1s core-level binding energies calculated from Green's function theory in the GW approximation, which does not add computational overhead. An element-specific corrective term is derived ... Full text Cite

Organic-to-inorganic structural chirality transfer in a 2D hybrid perovskite and impact on Rashba-Dresselhaus spin-orbit coupling.

Journal Article Nature communications · September 2020 Translation of chirality and asymmetry across structural motifs and length scales plays a fundamental role in nature, enabling unique functionalities in contexts ranging from biological systems to synthetic materials. Here, we introduce a structural chiral ... Full text Cite

Pentacene and tetracene molecules and films on H/Si(111): Level alignment from hybrid density functional theory

Journal Article Electronic Structure · September 1, 2020 The electronic properties of hybrid organic-inorganic semiconductor interfaces depend strongly on the alignment of the electronic carrier levels in the organic/inorganic components. In the present work, we address this energy level alignment from first pri ... Full text Cite

Rational ligand choice extends the SABRE substrate scope.

Journal Article Chemical communications (Cambridge, England) · August 2020 Here we report on chelating ligands for Signal Amplification By Reversible Exchange (SABRE) catalysts that permit hyperpolarisation on otherwise sterically hindered substrates. We demonstrate 1H enhancements of ∼100-fold over 8.5 T thermal for 2 ... Full text Cite

Erratum: Structural tolerance factor approach to defect-resistant I2‑II-IV‑X4 semiconductor design (Chemistry of Materials (2020) 32:4 (1636-1649) DOI: 10.1021/acs.chemmater.9b05107)

Journal Article Chemistry of Materials · July 14, 2020 In our original manuscript, the energy band structure of Ag2PbSiS4 in the Ama2 structure, shown in Figure 11d and calculated at the level of the hybrid density functional HSE06, was mistakenly calculated without including the effects of spin- orbit couplin ... Full text Cite

The CECAM electronic structure library and the modular software development paradigm.

Journal Article The Journal of chemical physics · July 2020 First-principles electronic structure calculations are now accessible to a very large community of users across many disciplines, thanks to many successful software packages, some of which are described in this special issue. The traditional coding paradig ... Full text Cite

Highly Distorted Chiral Two-Dimensional Tin Iodide Perovskites for Spin Polarized Charge Transport.

Journal Article Journal of the American Chemical Society · July 2020 Incorporating chiral organic molecules into organic/inorganic hybrid 2D metal-halide perovskites results in a novel family of chiral hybrid semiconductors with unique spin-dependent properties. The embedded chiral organic moieties induce a chiroptical resp ... Full text Cite

Siesta: Recent developments and applications.

Journal Article The Journal of chemical physics · May 2020 A review of the present status, recent enhancements, and applicability of the Siesta program is presented. Since its debut in the mid-1990s, Siesta's flexibility, efficiency, and free distribution have given advanced materials simulation capabilities to ma ... Full text Cite

Frenkel-Holstein Hamiltonian applied to absorption spectra of quaterthiophene-based 2D hybrid organic-inorganic perovskites.

Journal Article The Journal of chemical physics · April 2020 For the prototypical two-dimensional hybrid organic-inorganic perovskites (2D HOIPs) (AE4T)PbX4 (X = Cl, Br, and I), we demonstrate that the Frenkel-Holstein Hamiltonian (FHH) can be applied to describe the absorption spectrum arising from the o ... Full text Cite

DFTB+, a software package for efficient approximate density functional theory based atomistic simulations.

Journal Article The Journal of chemical physics · March 2020 DFTB+ is a versatile community developed open source software package offering fast and efficient methods for carrying out atomistic quantum mechanical simulations. By implementing various methods approximating density functional theory (DFT), such as the ... Full text Cite

Structural Tolerance Factor Approach to Defect-Resistant I2-II-IV-X4 Semiconductor Design

Journal Article Chemistry of Materials · February 25, 2020 Recent work on quaternary semiconductors Cu2BaSn(S,Se)4 and Ag2BaSnSe4 for photovoltaic and thermoelectric applications, respectively, has shown the promise of exploring the broader family of defect-resistant I2-II-IV-X4 materials (where I, II, and IV refe ... Full text Open Access Cite

All-electron ab initio Bethe-Salpeter equation approach to neutral excitations in molecules with numeric atom-centered orbitals.

Journal Article The Journal of chemical physics · January 2020 The Bethe-Salpeter equation (BSE) based on GW quasiparticle levels is a successful approach for calculating the optical gaps and spectra of solids and also for predicting the neutral excitations of small molecules. We here present an all-electron implement ... Full text Cite

Molecular engineering of organic-inorganic hybrid perovskites quantum wells.

Journal Article Nature chemistry · December 2019 Semiconductor quantum-well structures and superlattices are key building blocks in modern optoelectronics, but it is difficult to simultaneously realize defect-free epitaxial growth while fine tuning the chemical composition, layer thickness and band struc ... Full text Cite

Resolving rotational stacking disorder and electronic level alignment in a 2d oligothiophene-based lead iodide perovskite

Journal Article Chemistry of Materials · October 22, 2019 Two-dimensional (2D) hybrid organic-inorganic perovskites (HOIPs) represent diverse quantum well heterostructures composed of alternating inorganic and organic layers. While 2D HOIPs are nominally periodic in three dimensions for X-ray scattering, the inor ... Full text Cite

Tunable internal quantum well alignment in rationally designed oligomer-based perovskite films deposited by resonant infrared matrix-assisted pulsed laser evaporation

Journal Article Materials Horizons · October 1, 2019 Hybrid perovskites incorporating conjugated organic cations enable unusual charge carrier interactions among organic and inorganic structural components, but are difficult to prepare as films due to disparate component chemical/physical characteristics (e. ... Full text Cite

Formation of graphene atop a Si adlayer on the C-face of SiC

Journal Article Physical Review Materials · August 19, 2019 The structure of the SiC(0001) surface, the C-face of the {0001} SiC surfaces, is studied as a function of temperature and of pressure in a gaseous environment of disilane (Si2H6). Various surface reconstructions are observed, both with and without the pre ... Full text Cite

Direct-Bandgap 2D Silver-Bismuth Iodide Double Perovskite: The Structure-Directing Influence of an Oligothiophene Spacer Cation.

Journal Article Journal of the American Chemical Society · May 2019 Three-dimensional (3D) hybrid organic-inorganic lead halide perovskites (HOIPs) feature remarkable optoelectronic properties for solar energy conversion but suffer from long-standing issues of environmental stability and lead toxicity. Associated two-dimen ... Full text Cite

Large-scale benchmark of electronic structure solvers with the ELSI infrastructure

Conference ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY · March 31, 2019 Link to item Cite

Tunable Semiconductors: Control over Carrier States and Excitations in Layered Hybrid Organic-Inorganic Perovskites.

Journal Article Physical review letters · October 2018 For a class of 2D hybrid organic-inorganic perovskite semiconductors based on π-conjugated organic cations, we predict quantitatively how varying the organic and inorganic component allows control over the nature, energy, and localization of carrier states ... Full text Cite

Band Gap Tailoring and Structure-Composition Relationship within the Alloyed Semiconductor Cu2BaGe1- xSnxSe4

Journal Article Chemistry of Materials · September 25, 2018 Recently, the I2-II-IV-VI4 (I = Cu, Ag; II = Ba, Sr; IV = Ge, Sn; VI = S, Se) materials family was identified as a promising source of potential new photovoltaic (PV) and photoelectrochemical (PEC) absorbers. These materials avoid the pitfalls of the succe ... Full text Cite

Thermodynamically accessible titanium clusters TiN, N = 2-32.

Journal Article Physical chemistry chemical physics : PCCP · May 2018 We have performed a genetic algorithm search on the tight-binding interatomic potential energy surface (PES) for small TiN (N = 2-32) clusters. The low energy candidate clusters were further refined using density functional theory (DFT) calculations with t ... Full text Cite

Large-scale first principles NMR calculations with numeric atom-centered basis sets

Conference ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY · March 18, 2018 Link to item Cite

ELSI: A unified software interface for Kohn-Sham electronic structure solvers

Conference ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY · March 18, 2018 Link to item Cite

GPU-accelerated large-scale electronic structure theory with a first-principles all-electron code

Conference ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY · March 18, 2018 Link to item Cite

ELSI: A unified software interface for Kohn–Sham electronic structure solvers

Journal Article Computer Physics Communications · January 1, 2018 Solving the electronic structure from a generalized or standard eigenproblem is often the bottleneck in large scale calculations based on Kohn–Sham density-functional theory. This problem must be addressed by essentially all current electronic structure co ... Full text Open Access Cite

Efficient Implicit Solvation Method for Full Potential DFT.

Journal Article Journal of chemical theory and computation · November 2017 With the advent of efficient electronic structure methods, effective continuum solvation methods have emerged as a way to, at least partially, include solvent effects into simulations without the need for expensive sampling over solvent degrees of freedom. ... Full text Cite

I2-II-IV-VI4 (I = Cu, Ag; II = Sr, Ba; IV = Ge, Sn; VI = S, Se): Chalcogenides for Thin-Film Photovoltaics

Journal Article Chemistry of Materials · September 26, 2017 Recent work has identified a non-zinc-blende-type quaternary semiconductor, Cu2BaSnS4-xSex (CBTSSe), as a promising candidate for thin-film photovoltaics (PVs). CBTSSe circumvents difficulties of competing PV materials regarding (i) toxicity (e.g., CdTe), ... Full text Cite

One-hundred-three compound band-structure benchmark of post-self-consistent spin-orbit coupling treatments in density functional theory

Journal Article Physical Review Materials · August 30, 2017 We quantify the accuracy of different non-self-consistent and self-consistent spin-orbit coupling (SOC) treatments in Kohn-Sham and hybrid density functional theory by providing a band-structure benchmark set for the valence and low-lying conduction energy ... Full text Cite

Long-Lived 13C2 Nuclear Spin States Hyperpolarized by Parahydrogen in Reversible Exchange at Microtesla Fields.

Journal Article The journal of physical chemistry letters · July 2017 Parahydrogen is an inexpensive and readily available source of hyperpolarization used to enhance magnetic resonance signals by up to four orders of magnitude above thermal signals obtained at ∼10 T. A significant challenge for applications is fast signal d ... Full text Cite

Urea-Modified Carbon Nitrides: Enhancing Photocatalytic Hydrogen Evolution by Rational Defect Engineering

Journal Article Advanced Energy Materials · June 21, 2017 The primary amine groups on the heptazine-based polymer melon, also known as graphitic carbon nitride (g-C3N4), can be replaced by urea groups using a two-step postsynthetic functionalization. Under simulated sunlight and optimum Pt loading, this urea-func ... Full text Cite

Earth-Abundant Chalcogenide Photovoltaic Devices with over 5% Efficiency Based on a Cu2 BaSn(S,Se)4 Absorber.

Journal Article Advanced materials (Deerfield Beach, Fla.) · June 2017 In recent years, Cu2 ZnSn(S,Se)4 (CZTSSe) materials have enabled important progress in associated thin-film photovoltaic (PV) technology, while avoiding scarce and/or toxic metals; however, cationic disorder and associated band tailin ... Full text Cite

Thermodynamic Equilibria in Carbon Nitride Photocatalyst Materials and Conditions for the Existence of Graphitic Carbon Nitride g-C3N4

Journal Article Chemistry of Materials · May 23, 2017 We quantify the thermodynamic equilibrium conditions that govern the formation of crystalline heptazine-based carbon nitride materials, currently of enormous interest for photocatalytic applications including solar hydrogen evolution. Key phases studied in ... Full text Cite

Subsurface structure fingerprint of 2D materials and heterostructures by their nanomechanical response

Conference ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY · April 2, 2017 Link to item Cite

Scalable all-electron theory of real-world molecules and materials - examples: Light harvesting and NMR

Conference ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY · April 2, 2017 Link to item Cite

The Elephant in the Room of Density Functional Theory Calculations.

Journal Article The journal of physical chemistry letters · April 2017 Using multiwavelets, we have obtained total energies and corresponding atomization energies for the GGA-PBE and hybrid-PBE0 density functionals for a test set of 211 molecules with an unprecedented and guaranteed μHartree accuracy. These quasi-exact refere ... Full text Cite

Candidate photoferroic absorber materials for thin-film solar cells from naturally occurring minerals: enargite, stephanite, and bournonite

Journal Article Sustainable Energy & Fuels · 2017 A search for photoactive ferroelectric minerals reveals three candidates, which are investigated using first-principles materials modelling. ... Full text Cite

Trends for isolated amino acids and dipeptides: Conformation, divalent ion binding, and remarkable similarity of binding to calcium and lead.

Journal Article Scientific reports · November 2016 We derive structural and binding energy trends for twenty amino acids, their dipeptides, and their interactions with the divalent cations Ca2+, Ba2+, Sr2+, Cd2+, Pb2+, and Hg2+. The underlyi ... Full text Cite

BaCu2Sn(S,Se)4: Earth-abundant chalcogenides for thin-film photovoltaics

Journal Article Chemistry of Materials · July 12, 2016 Chalcogenides such as CdTe, Cu(In,Ga)(S,Se)2 (CIGSSe), and Cu2ZnSn(S,Se)4 (CZTSSe) have enabled remarkable advances in thin-film photovoltaic performance, but concerns remain regarding (i) the toxicity (CdTe) and (ii) scarcity (CIGSSe/CdTe) of the constitu ... Full text Cite

Rational design of carbon nitride photocatalysts by identification of cyanamide defects as catalytically relevant sites

Journal Article Nature Communications · July 8, 2016 The heptazine-based polymer melon (also known as graphitic carbon nitride, g-C 3 N 4) is a promising photocatalyst for hydrogen evolution. Nonetheless, attempts to improve its inherently low activity are rarely based on rational approaches because of a lac ... Full text Cite

Quantitative Subsurface Atomic Structure Fingerprint for 2D Materials and Heterostructures by First-Principles-Calibrated Contact-Resonance Atomic Force Microscopy.

Journal Article ACS nano · July 2016 Interfaces and subsurface layers are critical for the performance of devices made of 2D materials and heterostructures. Facile, nondestructive, and quantitative ways to characterize the structure of atomically thin, layered materials are thus essential to ... Full text Cite

Rational design of carbon nitride photocatalysts by identification of cyanamide defects as catalytically relevant sites.

Journal Article Nature communications · July 2016 The heptazine-based polymer melon (also known as graphitic carbon nitride, g-C3N4) is a promising photocatalyst for hydrogen evolution. Nonetheless, attempts to improve its inherently low activity are rarely based on rational approaches because of a lack o ... Full text Cite

Direct and cost-efficient hyperpolarization of long-lived nuclear spin states on universal 15N2-diazirine molecular tags

Journal Article Science Advances · March 25, 2016 Conventional magnetic resonance (MR) faces serious sensitivity limitations which can be overcome by hyperpolarization methods, but the most common method (dynamic nuclear polarization) is complex and expensive, and applications are limited by short spin li ... Full text Open Access Link to item Cite

Continuum embedding for photo-electrochemical surface processes

Conference ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY · March 13, 2016 Link to item Cite

Reproducibility in density functional theory calculations of solids.

Journal Article Science (New York, N.Y.) · March 2016 The widespread popularity of density functional theory has given rise to an extensive range of dedicated codes for predicting molecular and crystalline properties. However, each code implements the formalism in a different way, raising questions about the ... Full text Cite

First-principles data set of 45,892 isolated and cation-coordinated conformers of 20 proteinogenic amino acids.

Journal Article Scientific data · February 2016 We present a structural data set of the 20 proteinogenic amino acids and their amino-methylated and acetylated (capped) dipeptides. Different protonation states of the backbone (uncharged and zwitterionic) were considered for the amino acids as well as var ... Full text Cite

Length dependence of ionization potentials of transacetylenes: Internally consistent DFT/ GW approach

Journal Article Physical Review B - Condensed Matter and Materials Physics · November 18, 2015 We follow the evolution of the ionization potential (IP) for the paradigmatic quasi-one-dimensional transacetylene family of conjugated molecules, from short to long oligomers and to the infinite polymer transpolyacetylene (TPA). Our results for short olig ... Full text Cite

First-Principles Molecular Structure Search with a Genetic Algorithm.

Journal Article Journal of chemical information and modeling · November 2015 The identification of low-energy conformers for a given molecule is a fundamental problem in computational chemistry and cheminformatics. We assess here a conformer search that employs a genetic algorithm for sampling the low-energy segment of the conforma ... Full text Cite

Accurate localized resolution of identity approach for linear-scaling hybrid density functionals and for many-body perturbation theory

Journal Article New Journal of Physics · September 11, 2015 A key component in calculations of exchange and correlation energies is the Coulomb operator, which requires the evaluation of two-electron integrals. For localized basis sets, these four-center integrals are most efficiently evaluated with the resolution ... Full text Open Access Cite

Hybrid functionals for large periodic systems in an all-electron, numeric atom-centered basis framework

Journal Article Computer Physics Communications · July 1, 2015 We describe a framework to evaluate the Hartree-Fock exchange operator for periodic electronic-structure calculations based on general, localized atom-centered basis functions. The functionality is demonstrated by hybrid-functional calculations of properti ... Full text Cite

All-electron formalism for total energy strain derivatives and stress tensor components for numeric atom-centered orbitals

Journal Article Computer Physics Communications · May 1, 2015 We derive and implement the strain derivatives of the total energy of solids, i.e., the analytic stress tensor components, in an all-electron, numeric atom-centered orbital based density-functional formalism. We account for contributions that arise in the ... Full text Cite

Why graphene growth is very different on the C face than on the Si face of SiC: Insights from surface equilibria and the (3×3)-3C-SiC(1¯ 1¯ 1¯) reconstruction

Journal Article Physical Review B - Condensed Matter and Materials Physics · April 17, 2015 We address the stability of the surface phases that occur on the C side of 3C-SiC(1¯1¯1¯) at the onset of graphene formation. In this growth range, experimental reports reveal a coexistence of several surface phases. This coexistence can be explained by a ... Full text Cite

Approaching truly freestanding graphene: the structure of hydrogen-intercalated graphene on 6H-SiC(0001).

Journal Article Physical review letters · March 2015 We measure the adsorption height of hydrogen-intercalated quasifreestanding monolayer graphene on the (0001) face of 6H silicon carbide by the normal incidence x-ray standing wave technique. A density functional calculation for the full (6√3×6√3)-R30° unit ... Full text Cite

Exploring the conformational preferences of 20-residue peptides in isolation: Ac-Ala19-Lys + H(+)vs. Ac-Lys-Ala19 + H(+) and the current reach of DFT.

Journal Article Physical chemistry chemical physics : PCCP · March 2015 Reliable, quantitative predictions of the structure of peptides based on their amino-acid sequence information are an ongoing challenge. We here explore the energy landscapes of two unsolvated 20-residue peptides that result from a shift of the position of ... Full text Cite

Native like helices in a specially designed β peptide in the gas phase.

Journal Article Physical chemistry chemical physics : PCCP · February 2015 In the natural peptides, helices are stabilized by hydrogen bonds that point backward along the sequence direction. Until now, there is only little evidence for the existence of analogous structures in oligomers of conformationally unrestricted β amino aci ... Full text Cite

Low-molecular-weight carbon nitrides for solar hydrogen evolution.

Journal Article Journal of the American Chemical Society · January 2015 This work focuses on the control of the polymerization process for melon ("graphitic carbon nitride"), with the aim of improving its photocatalytic activity intrinsically. We demonstrate here that reduction of the synthesis temperature leads to a mixture o ... Full text Cite

How mono-valent cations bend peptide turns and a first-principles database of amino acids and dipeptides

Conference AIP Conference Proceedings · October 6, 2014 In this contribution we detail our efforts to investigate the structural effects of cations binding to peptides and amino acids. We perform first-principles studies employing long-range dispersion-corrected approximate density-functional theory and compare ... Full text Cite

Validation challenge of density-functional theory for peptides-example of Ac-Phe-Ala5-LysH(+).

Journal Article J Phys Chem A · September 4, 2014 We assess the performance of a group of exchange-correlation functionals for predicting the secondary structure of peptide chains, up to a new many-body dispersion corrected hybrid density functional, dubbed PBE0+MBD* by its original authors. For the purpo ... Full text Link to item Cite

Embedded-cluster calculations in a numeric atomic orbital density-functional theory framework.

Journal Article The Journal of chemical physics · July 2014 We integrate the all-electron electronic structure code FHI-aims into the general ChemShell package for solid-state embedding quantum and molecular mechanical (QM/MM) calculations. A major undertaking in this integration is the implementation of pseudopote ... Full text Cite

Isomerism and structural fluxionality in the Au26 and Au26(-) nanoclusters.

Journal Article ACS nano · July 2014 Using the minima hopping global optimization method at the density functional level, we found low-energy nanostructures for neutral Au26 and its anion. The local-density and a generalized gradient approximation of the exchange–correlation functional predic ... Full text Cite

The ELPA library: scalable parallel eigenvalue solutions for electronic structure theory and computational science.

Journal Article Journal of physics. Condensed matter : an Institute of Physics journal · May 2014 Obtaining the eigenvalues and eigenvectors of large matrices is a key problem in electronic structure theory and many other areas of computational science. The computational effort formally scales as O(N(3)) with the size of the investigated problem, N (e. ... Full text Cite

Is there a Beta-Peptide Equivalent of the Alpha-Helix?

Conference Biophysical Journal · January 2014 Full text Cite

Structural investigation of nanocrystalline graphene grown on (6√3 × 6√3)R30°-reconstructed SiC surfaces by molecular beam epitaxy

Journal Article New Journal of Physics · December 1, 2013 Growth of nanocrystalline graphene films on (6√3 × 6√3)R30°-reconstructed SiC surfaces was achieved by molecular beam epitaxy, enabling the investigation of quasi-homoepitaxial growth. The structural quality of the graphene films, which is investigated by ... Full text Cite

Numeric atom-centered-orbital basis sets with valence-correlation consistency from H to Ar

Journal Article New Journal of Physics · December 1, 2013 We present a series of numerically tabulated atom-centered orbital (NAO) basis sets with valence-correlation consistency (VCC), termed NAO-VCC-nZ. Here the index 'nZ' refers to the number of basis functions used for the valence shell with n = 2, 3, 4, 5. T ... Full text Cite

Materials and nanostructures, the all-electron way: FHI-aims

Conference ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY · September 8, 2013 Link to item Cite

Thermodynamic equilibrium conditions of graphene films on SiC

Journal Article Physical Review Letters · August 6, 2013 Full text Cite

How cations change peptide structure.

Journal Article Chemistry (Weinheim an der Bergstrasse, Germany) · August 2013 Specific interactions between cations and proteins have a strong impact on peptide and protein structure. Herein, we shed light on the nature of the underlying interactions, especially regarding effects on the polyamide backbone structure. This was done by ... Full text Cite

Isomer-Selective Detection of Hydrogen-Bond Vibrations in the Protonated Water Hexamer

Journal Article Journal of the American Chemical Society · 2013 Cite

Benchmarking the Water-Peptide Interaction

Conference Biophysical Journal · January 2013 Full text Cite

Water adsorption at two unsolvated peptides with a protonated lysine residue: from self-solvation to solvation.

Journal Article The journal of physical chemistry. B · December 2012 We study the initial steps of the interaction of water molecules with two unsolvated peptides: Ac-Ala(5)-LysH(+) and Ac-Ala(8)-LysH(+). Each peptide has two primary candidate sites for water adsorption near the C-terminus: a protonated carboxyl group and t ... Full text Cite

Impact of vibrational entropy on the stability of unsolvated peptide helices with increasing length

Journal Article · August 2012 Helices are a key folding motif in protein structure. The question which factors determine helix stability for a given polypeptide or protein is an ongoing challenge. Here we use van der Waals corrected density-functional theory to address a part of this q ... Cite

Pushing all-electron DFT past old limits for structure of surfaces and molecules

Conference Acta Crystallographica Section A Foundations of Crystallography · August 22, 2011 Full text Cite

< i> Ab initio molecular simulations with numeric atom-centered orbitals

Journal Article Computer Physics Communications · 2009 Cite

The Pd (1 0 0) - (sqrt(5) × sqrt(5)) R 27 ° s(-) O surface oxide: A LEED, DFT and STM study

Journal Article Surface Science · March 15, 2007 Using low energy electron diffraction (LEED), density functional theory (DFT) and scanning tunneling microscopy (STM), we have re-analyzed the Pd (1 0 0) - (sqrt(5) × sqrt(5)) R 27 ° s(-) O surface oxide structure consisting, in the most recent model, of a ... Full text Cite

Prediction of unusual stable ordered structures of Au-Pd alloys via a first-principles cluster expansion

Journal Article Physical Review B - Condensed Matter and Materials Physics · July 20, 2006 We describe an iterative procedure which yields an accurate cluster expansion for Au-Pd using only a limited number of ab initio formation enthalpies. Our procedure addresses two problems: (a) given the local-density-approximation (LDA) formation energies ... Full text Cite

Role of Co antisite segregation in the CoAl(111) surface

Journal Article Physical Review B - Condensed Matter and Materials Physics · February 1, 2005 The geometrical and chemical structure of the CoAl(111) surface is investigated by quantitative low-energy electron diffraction and calculations applying density functional theory. The stacking sequence of the top four atomic planes is Al-Co-Co-Co, followe ... Full text Cite

Structural complexity in binary bcc ground states: The case of bcc Mo-Ta

Journal Article Physical Review B - Condensed Matter and Materials Physics · 2004 Traditional sorting diagrams for ground states (T=0 stable atomic configurations) of bcc-based binary alloys predict simple crystal structures when simple parametric interactions (e.g., first few pairs) are assumed. However, the range and magnitude of inte ... Cite

Competitive surface segregation of C, Al and S impurities in Fe(100)

Journal Article Journal of Physics Condensed Matter · June 4, 2003 The stoichiometries and geometric structures formed by the segregation of C, Al and S on a Fe(100) surface have been investigated by Auger electron spectroscopy and quantitative low-energy electron diffraction (LEED). Stepwise annealing of a sputtered surf ... Full text Cite

Equilibration processes in surfaces of the binary alloy Fe-Al

Journal Article Journal of Physics Condensed Matter · April 29, 2002 The scenario of geometrical relaxation or reconstruction known for the surfaces of elemental solids is enriched by surface segregation in the case of compound surfaces. Both phenomena are consequences of the mere creation of the surface in which atoms in a ... Full text Cite

Structure of the c(2×2)-Br/Pt(110) surface

Journal Article Physical Review B - Condensed Matter and Materials Physics · 2002 We present a detailed investigation of the c(2×2)-Br/Pt(110) adlayer structure supplemented by the analysis of the (1×2) missing-row (MR) structure of the clean Pt(110) surface. Quantitative low energy electron diffraction analyses and first-principles cal ... Cite

Structure of the (formula presented)-Br/Pt(110) surface

Journal Article Physical Review B - Condensed Matter and Materials Physics · January 1, 2002 We present a detailed investigation of the (formula presented) adlayer structure supplemented by the analysis of the (formula presented) missing-row (MR) structure of the clean Pt(110) surface. Quantitative low energy electron diffraction analyses and firs ... Full text Cite

Quantification of substitutional disorder and atomic vibrations by LEED - The role of parameter correlations

Journal Article Surface Science · August 1, 2001 The composition of substitutionally disordered surfaces, including the layer and site dependent distribution of the chemical elements involved, has frequently been a target of quantitative low-energy electron diffraction. In the present paper, we demonstra ... Full text Cite

Equilibration of stoichiometrically distorted Fe1-xAlx(100) surfaces

Journal Article Journal of Physics Condensed Matter · March 5, 2001 The correlation between segregation kinetics and the geometric and chemical structure of iron-rich Fe1-xAlx (100) surfaces was investigated for four samples with different bulk stoichiometries (x = 0.03, 0.15, 0.30, 0.47) using quantitative low-energy elec ... Full text Cite

Segregation and ordering at Fe1-xAlx(1 0 0) surfaces - a model case for binary alloys

Journal Article Surface Science · March 1, 2001 The geometrical structure, chemical order and composition of (1 0 0) oriented surfaces of the binary alloy system Fe1-xAlx were investigated in the Fe-rich regime (x = 0.03, 0.15, and 0.30) using quantitative low-energy electron diffraction. Low-energy He+ ... Full text Cite

Role of an energy-dependent inner potential in quantitative low-energy electron diffraction

Journal Article Surface Science · June 20, 2000 Recent apparent discrepancies between results from low-energy electron and X-ray diffraction concerning a reduced in-plane lattice parameter of Cu(100) are resolved in favour of an uncontracted surface. We show that neglecting the energy dependence of the ... Full text Cite

Fe thin-film growth on au(100): a self-surfactant effect and its limitations

Journal Article Physical Review B - Condensed Matter and Materials Physics · January 1, 1999 The combination of low-energy electron diffraction intensity analyses and scanning tunneling microscopy was used to investigate the morphology and atomic structure of thin Fe films grown on Au(100) at 400 K. Deposition of only about 0.2 monolayers (ML) Fe ... Full text Cite

Segregation phenomena on surfaces of the ordered bimetallic alloy FeAl

Journal Article Surface Science · September 3, 1998 The segregation and ordering behavior of the (100), (110), (210), (310) and (111) surfaces of the ordered intermetallic compound FeAl were investigated by means of AES and LEED. Starting from preferentially sputtered, i.e. Al-depleted surfaces sequential a ... Full text Cite

Extending holographic LEED to ordered small-unit-cell superstructures

Journal Article Physical Review B - Condensed Matter and Materials Physics · January 1, 1998 Following on the success of the recent application of holographic LEED to the determination of the three-dimensional atomic geometry of Si adatoms on a (Formula presented) surface, which enabled that structure to be solved, we show in this paper that a sim ... Full text Cite

Ordered and disordered rippling in the CoAl(110)-(1 × 1) surface

Journal Article Surface Review and Letters · 1996 A quantitative structural analysis of CoAl(110)-(1 × 1) by low energy electron diffraction shows that the topmost layer of the surface is rippled by an amplitude of 0.18 Å, with aluminum atoms pulled out of the surface and the average distance to the secon ... Cite

Ordered and disordered rippling in the CoAl(110)-(1 × 1) surface

Journal Article Surface Review and Letters · January 1, 1996 A quantitative structural analysis of CoAl(110)-(1 × 1) by low energy electron diffraction shows that the topmost layer of the surface is rippled by an amplitude of 0.18 Å, with aluminum atoms pulled out of the surface and the average distance to the secon ... Full text Cite