In-plane anisotropy in two-dimensional electron gas at LaAlO_3/SrTiO_3(110) interface

A systematic study of the two-dimensional electron gas at LaAlO₃/SrTiO₃(110) interface reveals an anisotropy along two specific directions, 001] and 111]. The anisotropy becomes distinct for the interface prepared under high oxygen pressure with low carrier density. Angular dependence of magnetoresistance shows that the electron confinement is stronger along the 111] direction. Gate-tunable magnetoresistance reveals a clear in-plane anisotropy of the spin-orbit coupling, and the spin relaxation mechanism along both directions belongs to D'yakonov-Perel' (DP) scenario. Moreover, in-plane anisotropic superconductivity is observed for the sample with high carrier density, the superconducting transition temperature is lower but the upper critical field is higher along the 111] direction. This in-plane anisotropy could be ascribed to the anisotropic band structure along the two crystallographic directions.