Magnetic Field Driven Intersection of Spin-Split Fermi Contours in the (111) LaTiO3/SrTiO3 Interface

When systems containing spin-orbit interaction are subjected to a magnetic field, the Fermi surface becomes asymmetric, resulting in non-linear transport components (V ∼I 2 ). In this talk, I will show that by focusing on such non-linear transport effects, the role of spin-orbit interaction in the (111) LaTiO3/SrTiO3 interface can be understood. We observed that the non-linear resistance exhibits a dramatic increase at a critical in-plane magnetic field Hc. Furthermore, we find that this increase vanishes when a minuscule out-of-plane magnetic field is applied. By employing a minimal model that incorporates Rashba-type spin-orbit interaction, we demonstrate that these results can be explained by the intersection of the spin-split Fermi contours at the critical field Hc. The presence of an out-of-plane magnetic field opens a gap through the Zeeman interaction, which we show to substantially diminish the effect. We speculate that certain magnetoresistance effects previously observed in various interfaces could be understood within the framework of the Fermi contour intersection studied here.