Strong correlations elucidate the electronic structure and phase diagram of LaAlO3/SrTiO3 interface

Nat Commun. 2015 Sep 11:6:8239. doi: 10.1038/ncomms9239.

Abstract

The interface between the two band insulators SrTiO3 and LaAlO3 has the unexpected properties of a two-dimensional electron gas. It is even superconducting with a transition temperature, T(c), that can be tuned using gate bias V(g), which controls the number of electrons added or removed from the interface. The gate bias-temperature (V(g), T) phase diagram is characterized by a dome-shaped region where superconductivity occurs, that is, T(c) has a non-monotonic dependence on V(g), similar to many unconventional superconductors. Here, we report, the frequency of the quantum resistance-oscillations versus inverse magnetic field for various V(g). This frequency follows the same non-monotonic behaviour as T(c); a similar trend is seen in the low field limit of the Hall coefficient. We theoretically show that electronic correlations result in a non-monotonic population of the mobile band, which can account for the experimental behaviour of the normal transport properties and the superconducting dome.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.