Possible mechanisms of electronic phase separation in oxide interfaces

LaAlO3 /SrTiO3 and LaTiO3 /SrTiO3 (LXO / STO) interfaces are known to host a strongly inhomoge- neous (nearly) two-dimensional electron gas (2DEG). In this work, we present three unconventional electronic mech- anisms of electronic phase separation (EPS) in a 2DEG as a possible source of inhomogeneity in oxide interfaces. Common to all three mechanisms is the dependence of some (interaction) potential on the 2DEGs density. We first consider a mechanism resulting from a sizable density- dependent Rashba spin-orbit coupling. Next, we point out that an EPS may also occur in the case of a density- dependent superconducting pairing interaction. Finally, we show that the confinement of the 2DEG to the interface by a density-dependent, self-consistent electrostatic potential can by itself cause an EPS.