Six-fold crystalline anisotropic magnetoresistance in (111) LaAlO3/SrTiO3 oxide interface

We measured the magnetoresistance of the 2D electron liquid formed at the (111) SrTiO$_3$/LaAlO$_3$ interface. The hexagonal symmetry of the interface is manifested in a six-fold crystalline component appearing in the anisotropic magnetoresistance (AMR) and planar Hall data, which agree well with symmetry analysis we performed. The six-fold component increases with carrier concentration, reaching 15% of the total AMR signal. The AMR and planar Hall data are consistent for a 2D hexagonal system. Our results suggest that the coupling between higher itinerant electronic bands and the crystal as the origin of this effect, and demonstrate that (111) oxide interface is a unique hexagonal system with tunable magneto-crystalline effects.