Understanding the electric-field enhancement of the superconducting transition temperature for complex oxide interfaces

We examine the enhancement of the interfacial superconductivity between LaAlO sub(3) and SrTiO sub(3) by an effective electric field. Through the breaking of inversion symmetry at the interface, we show that a term in the free energy, coupling the superfluid density and an electric field, can augment the superconductivity transition temperature. Microscopically, we show that an electric field can also produce changes in the carrier density by relating the measured capacitance to the density of states. Through the standard BCS (Bardeen, Cooper, and Schrieffer) weak-coupling interaction in bulk SrTiO sub(3), we estimate the transition temperature.