In-plane anisotropy in two-dimensional electron gas at LaAlO₃/SrTiO₃(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.