Rashba spin splitting in two-dimensional electron gas in polar-polar perovskite oxide heterostructure LaVO3/KTaO3: A DFT investigation

Abstract

Perovskite oxide surfaces and their interfaces host two-dimensional electron gas (2DEG) and many other emergent properties. Polar-polar perovskite oxide heterostructure LaVO3/KTaO3 with the n-type interface is studied using comprehensive first principle calculations. Our calculations involve crystal orientation-dependent investigation of 2DEG for two types of terminations of KTO surface slab namely asymmetric and symmetric terminations in [001] and [111] orientations. Electronic structure calculations show n-type conducting interface and the Rashba spin splitting in the bands with αR in the range 0.37−0.9eVÅ and ER in the range of 0.6−4.5eV owing to the high spin–orbit coupling of Ta and symmetry breaking electric field present in the heterostructure. The occupation of heavy bands dyz/dxz and the additional occupation of dz2 bands in [111] orientation give rise to orbital-dependent Rashba splitting. The charge density difference plots corroborate the transfer of charge from the surface to the interfacial region. Constant energy contour plots of spin texture confirm the 2D Rashba spin splitting of 2DEG in [001] orientation, while a complex spin structure is observed in [111] orientation. Thus, our findings extend the scope of perovskite-based heterostructures for future spintronic applications maneuvering the Rashba effect with a fascinating spin structure.