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Multiple experiments have observed a sharp transition in the band structure of LaAlO$_3$/SrTiO$_3$ (001) interfaces as a function of applied gate voltage. This Lifshitz transition, between a single occupied band at low electron density and multiple occupied bands at high density, is remarkable for its abruptness. In this work, we propose a mechanism by which such a transition might happen. We show via numerical modeling that the simultaneous coupling of the dielectric polarization to the interfacial strain (electrostrictive coupling) and strain gradient (flexoelectric coupling) generates a thin polarized layer whose direction reverses at a critical density. The Lifshitz transition occurs concomitantly with the polarization reversal and is first-order at $T=0$. A secondary Lifshitz transition, in which electrons spread out into semiclassical tails, occurs at a higher density.
A number of recent studies indicate that the charge conduction of the LaAlO$_3$/SrTiO$_3$ interface at low temperature is confined to filaments which are linked to structural domain walls in the SrTiO$_3$ with drastic consequences for example for the
Novel electronic systems forming at oxide interfaces comprise a class of new materials with a wide array of potential applications. A high mobility electron system forms at the LaAlO$_3$/SrTiO$_3$ interface and, strikingly, both superconducts and dis
At the LaAlO$_3$-SrTiO$_3$ interface, electronic phase transitions can be triggered by modulation of the charge carrier density, making this system an excellent prospect for the realization of versatile electronic devices. Here, we report repeatable
Localization of electrons in the two-dimensional electron gas at the LaAlO$_3$/SrTiO$_3$ interface is investigated by varying the channel thickness in order to establish the nature of the conducting channel. Layers of SrTiO$_3$ were grown on NdGaO$_3
The 2-dimensional electron system at the interface between LaAlO$_{3}$ and SrTiO$_{3}$ has several unique properties that can be tuned by an externally applied gate voltage. In this work, we show that this gate-tunability extends to the effective ban