title: Intrinsic instability of electronic interfaces with strong Rashba coupling.
abstract: We consider a model for the two-dimensional electron gas formed at the interface of oxide heterostructures, which includes a Rashba spin-orbit coupling proportional to the electric field perpendicular to the interface. Based on the standard mechanism of polarity catastrophe, we assume that the electric field has a contribution proportional to the electron density. Under these simple and general assumptions, we show that a phase separation instability (signaled by a negative compressibility) occurs for realistic values of the spin-orbit coupling and of the electronic band-structure parameters. This provides an intrinsic mechanism for the inhomogeneous phases observed at the LaAlO(3)/SrTiO(3) or LaTiO(3)/SrTiO(3) interfaces.
authors.affiliation: Dipartimento di Fisica, Università di Roma La Sapienza, P Aldo Moro 5, 00185 Roma, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Caprara
authors.forename: F
authors.initials: F
authors.lastname: Peronaci
authors.forename: M
authors.initials: M
authors.lastname: Grilli