First-principles study of Rashba effect in the (LaAlO₃)₂/(SrTiO₃)₂

Abstract

We have performed first-principles density functional calculations for superlattice composed of two oxide insulators, (LaAlO₃)₂/(SrTiO₃)₂. Calculated band structures show interface-induced metallic states. We found electron doping in the TiO₂ layer at LaO interface and hole doping in the AlO₂ layer at SrO interface. Due to the built-in electric field at the interface, the interface states show spin splitting and vortex-like spin textures in momentum space, i.e. Rashba effect. Calculated Rashba coefficient α_R, 12.6 meV Å, is of the same order as that of the experimental value.

Keywords::

• first-principles
• artificial superlattice
• Rashba effect

Funding

The work was partially supported by Grants-in-Aid on Scientific Research [grant number 25104714], [grant number 25790007], [grant number 25390008] from Japan Society for the Promotion of Science, and by the MEXT HPCI Strategic Program. Computations in this research were performed using supercomputers at the Institute for Solid State Physics (ISSP), the University of Tokyo, and supercomputers at RIIT, Kyushu University. The structure of artificial superlattice in Figure 1 is visualised using the program VESTA.[18]

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

^1. We evaluated electric field from the energy difference of shallow core Ti 3s state at the LaO interface and SrO interface.