Elucidating the Surface Properties of Sr3PbO Inverse‐Perovskite Topological Insulator: A First‐Principles Study

Abstract

The emergence of robust surface electronic states in topological insulators such as bulk Sr3PbO inverse‐perovskite makes them suitable candidates for spintronic devices and solid‐state quantum computers. Herein, the atomic structure, surface energetics, and electronic properties of Sr3PbO inverse‐perovskite Sr2O (SO)‐terminated and SrPb‐terminated (001) surfaces are examined using density functional theory. A comparison of the computed structural properties of SO‐termianted and SrPb‐terminated (001) surfaces reveals maximum surface rumpling and changes in interlayer distances for the SrPb‐terminated surface of Sr3PbO. However, the calculated surface energies indicate that both SO‐termianted and SrPb‐terminated (001) surfaces of Sr3PbO are energetically feasible, indicating that these surfaces can coexist in a polycrystalline sample of this material. Due to the presence of Pb in Sr3PbO, a comprehensive examination of the electronic structure of bulk and supercell slab structures of Sr3PbO by taking spin–orbit coupling effects into consideration is conducted. Noninsulating nature of electronic structure for the two possible (001) terminations of Sr3PbO is found. The domination of Pb‐6p states at the Fermi energy and the hole screening observed at the SrPb‐terminated surface of Sr3PbO support the p‐type nature observed in the experiment.