Aperiodic quantum oscillations in the two-dimensional electron gas at the LaAlO3/SrTiO3 interface

TL;DR

This study reveals complex, non-linear quantum oscillations in the two-dimensional electron gas at the LaAlO3/SrTiO3 interface, providing new insights into its electronic structure through advanced magneto-transport analysis.

Contribution

It demonstrates the occurrence of 1/B-aperiodic Shubnikov-de Haas oscillations and explains them using the Roth-Gao-Niu equation, linking experimental data with theoretical models.

Findings

Observation of non-linear Landau plots

Identification of 1/B-aperiodic quantum oscillations

Correlation with density functional theory calculations

Abstract

Despite several attempts, the intimate electronic structure of two-dimensional electron systems buried at the interface between LaAlO3 and SrTiO3 still remains to be experimentally revealed. Here, we investigate the transport properties of a high-mobility quasi-two-dimensional electron gas at this interface under high magnetic field (55 T) and provide new insights for electronic band structure by analyzing the Shubnikov-de Haas oscillations. Interestingly, the quantum oscillations are not 1/B-periodic and produce a highly non-linear Landau plot (Landau level index versus 1/B). Among possible scenarios, the Roth-Gao-Niu equation provides a natural explanation for 1/B-aperiodic oscillations in relation with the magnetic response functions of the system. Overall, the magneto-transport data are discussed in light of high-resolution scanning transmission electron microscopy analysis of the interface as well as calculations from density functional theory.