Charge-to-spin conversion in the quasi-two-dimensional electron gas emerging at the hydrogen-doped interface between LiNbO3 and LaAlO3

An oxide interface may become conducting when one oxide is polar, such as LaAlO3 (LAO) grown on SrTiO3 (001). We anticipate that the functional use of a solid electrolyte LiNbO3 (LiNO) in LAO/LiNO allows one to tune the quasi-two-dimensional electron gas (q2DEG) which emerges there. This phenomenon can be achieved by charging and discharging lithium niobate. In this paper, on the basis of ab initio calculations of the hydrogen-doped LAO/LiNO interface, we demonstrate how the q2DEG and its spin polarization appear. The out-of-plane electric polarization of LAO/LiNO forces the H dopants to accommodate at the Al-terminated interface. This results in the formation of the q2DEG, whose spatial extent is about 1.5 nm along the stacking direction. Since the spin-orbit coupling stimulates the spin textures in q2DEG, we believe that the charge current via the q2DEG may generate a variety of spin-orbitronic effects.