Strain induced Rashba splitting in CH3NH3PbBr3 organic–inorganic lead halide perovskite

Recently, it has been demonstrated that CH3NH3PbBr3 exhibits extraordinary giant Rashba splitting, which represents great opportunity for applications in spintronics and orbitronics. In this work, the strain induced Rashba band splitting of CH3NH3PbBr3 with various lattice constants from 5.4 Å to 6.4 Å has been investigated in detail by means of density functional theory including the spin–orbit coupling using full-relativistic pseduopotential. The calculation results indicate that the triple states at the conduction band maximum can be split by both spin–orbit coupling and strain. The details of the band structure at the conduction band maximum further reveal that the Rashba band splitting is strongly anisotropic along different directions due to the distortion of the Pb–Br octahedron. The maximum Rashba coefficient can be up to 2.0 eV Å at the equilibrium lattice constant. Furthermore, the Rashba coefficient is approximately linearly dependent on the strain in the range of ±5%. The Rashba coefficient can be even increased by nearly two times if CH3NH3PbBr3 is compressed by about 5%. Such strain induced Rashba coefficient enhancement may be useful for the application of CH3NH3PbBr3 in spintronic and orbitronic devices.