Tin-pest problem as a test of density functionals using high-throughput calculations

At ambient pressure tin transforms from its ground state, the semimetal α-Sn (diamond structure), to metallic β-Sn at 13°C (286 K). There may be a further transition to a simple hexagonal phase, γ-Sn, above 450 K. These relatively low transition temperatures are due to the small energy differences between the structures, ≈20 meV/atom between α- and β-Sn, which makes tin an exceptionally sensitive test of the accuracy of density functionals and computational methods used in calculating electronic and vibrational energy, including zero-point energy. Here we use the high-throughput automatic-flow (AFLOW) method to study the energetics of tin in multiple structures using a variety of density functionals and examine the vibrational contributions to the free energy with the AFLOW Automatic Phonon Library (APL). We look at the successes and deficiencies of each functional. We also discuss the necessity of testing high-throughput calculations for convergence of systems with small energy differences.

Duke Scholars

Author Stefano Curtarolo Thomas Lord Department of Mechanical Engineering and Materia ...