# Anomalous Quantum Oscillations of Interacting Electron-hole Gases in Inverted Type-II InAs/GaSb Quantum Wells

## TL;DR

This study reveals unusual quantum oscillations in InAs/GaSb quantum wells near charge neutrality, attributed to Coulomb interactions between electron and hole gases, challenging single-particle models.

## Contribution

It provides experimental evidence of Coulomb drag effects causing anomalous quantum oscillations in topological insulator quantum wells.

## Key findings

- Inverse periodic quantum oscillations observed
- High frequency oscillations despite high resistance
- Coulomb interactions are key to understanding phenomena

## Abstract

We report magneto-transport studies of InAs/GaSb bilayer quantum wells in a regime where the interlayer tunneling between the electron and hole gases is suppressed. When the chemical potential is tuned close to the charge neutrality point, we observe anomalous quantum oscillations that are inversely periodic in magnetic field and that have an extremely high frequency despite the highly insulating regime where they are observed. The seemingly contradictory coexistence of a high sheet resistance and high frequency quantum oscillations in the charge neutrality regime cannot be understood within the single-particle picture. We propose an interpretation that attributes our experimental observation to the Coulomb drag between the electron and hole gases, thus providing strong evidence of the significance of Coulomb interaction in this topological insulator.