Proximity-Induced Rashba Spin-Orbit Interaction in BaMnO$_\text{3}|$KTaO$_\text{3}$ Heterostructure for Antiferromagnetic Spintronics

Abstract: We investigate the emergence of Rashba-like spin-orbit interaction in the antiferromagnetic BaMnO$3|$KTaO$_3$ oxide heterostructure using density functional theory (DFT). The analysis of our charge transfer model based on electrostatic potential reveals a type-I band alignment and establishes the conditions under which the interface becomes conducting. Our calculations uncover pronounced linear Rashba splitting ($\alpha{(1)}$ = 0.114~eV\AA) in Mn 3$d$ bands near the Fermi level, induced by proximity to Ta 5$d$ orbitals of the KTO substrate. The heterostructure exhibits inversion asymmetry due to polar discontinuities at its $p$-type and $n$-type interfaces. Using three-dimensional band dispersions and projected spin textures along with isoenergetic contours obtained from DFT calculations, we confirm the linear Rashba nature of the spin-orbit coupling. Employing Monte Carlo simulations based on DFT-derived magnetic exchange interactions, we estimate a N\'{e}el temperature of approximately $\sim 54 \mathrm{~K}$. Our results demonstrate a viable route to engineering strong spin-orbit coupling in centrosymmetric antiferromagnets for spintronics applications.