Hidden anisotropy for electrons at a 2D oxide interface*

The recent discovery of 2D superconductivity at interfaces of  the strongly spin-orbit coupled cubic perovskite KTaO₃ (KTO) offers a new playground for exploring emergent quantum phenomenon. Here we report on observation of anisotropic transport properties within KTO (110) two-dimensional electron gases (2DEG). When the KTO (110) 2DEG  is realized using non-magnetic overlayers, we observe anisotropy similar to that found in 2DEGs at SrTiO₃ (110) interfaces. However,  when the KTO (110) 2DEG is realized using a magnetic overlayer, we find anisotropic behavior that is consistent with an anisotropic spin susceptibility, which suggests a peculiar spin texture at the Fermi surface. In particular, the critical fields for 2D superconductivity in heterostructures with magnetic overlayer along different crystal axis shows a competition between orbital and spin susceptibilities. In addition, we observed an anisotropic enhancement of quantum interference of the 2D electrons within the heterostructure with magnetic overlayer at low temperature.