Effect of surface termination on the electronic properties of LaNiO3 films

The electronic and structural properties of thin LaNiO3 films grown by using molecular beam epitaxy are studied as a function of the net ionic charge of the surface terminating layer. We demonstrate that electronic transport in nickelate heterostructures can be manipulated through changes in the surface termination due to a strong coupling of the surface electrostatic properties to the structural properties of the Ni - O bonds that govern electronic conduction. We observe experimentally and from first-principles theory an asymmetric response of the structural properties of the films to the sign of the surface charge, which results from a strong interplay between electrostatic and mechanical boundary conditions governing the system. The structural response results in ionic buckling in the near-surface NiO2 planes for films terminated with negatively charged NiO2 and bulklike NiO2 planes for films terminated with positively charged LaO planes. The ability to modify transport properties by the deposition of a single atomic layer can be used as a guiding principle for nanoscale device fabrication.

Duke Scholars

Author Divine P Kumah Physics