Two-dimensional quantum oscillations of the conductance at LaAlO3/SrTiO3 interfaces

TL;DR

This study reveals two-dimensional quantum oscillations in LaAlO3/SrTiO3 interfaces, showing multiple sub-band occupation and effective mass, with electric fields enhancing mobility and carrier density.

Contribution

It provides the first detailed analysis of quantum oscillations indicating 2D Fermi surface and multi-band effects at LaAlO3/SrTiO3 interfaces.

Findings

Observation of Shubnikov-de Haas oscillations confirming 2D Fermi surface

Identification of multiple sub-bands or valleys in the quantum well

Electric field increases mobility, carrier density, and oscillation frequency

Abstract

We report on a study of magnetotransport in LaAlO3/SrTiO3 interfaces characterized by mobilities of the order of several thousands cm$^{2}$/Vs. We observe Shubnikov-de Haas oscillations that indicate a two-dimensional character of the Fermi surface. The frequency of the oscillations signals a multiple sub-bands occupation in the quantum well or a multiple valley configuration. From the temperature dependence of the oscillation amplitude we extract an effective carrier mass $m^{*}\simeq1.45$\,$m_{e}$. An electric field applied in the back-gate geometry increases the mobility, the carrier density and the oscillation frequency.