Anti-crossings of spin-split Landau levels in an InAs two-dimensional electron gas with spin-orbit coupling

TL;DR

This study investigates anti-crossings of spin-split Landau levels in an InAs quantum well, revealing the influence of spin-orbit coupling, band non-parabolicity, and electron-electron interactions on Landau level behavior in the quantum Hall regime.

Contribution

It provides new insights into the effects of spin-orbit coupling and electron interactions on Landau level anti-crossings in narrow-gap semiconductor systems.

Findings

Observation of anti-crossings indicating spin state mixing

Significant electron-electron interaction effects on g-factor

Role of spin-orbit and band non-parabolicity in level repulsion

Abstract

We report tilted-field transport measurements in the quantum-Hall regime in an InAs/In_0.75Ga_0.25As/In_0.75Al_0.25As quantum well. We observe anti-crossings of spin-split Landau levels, which suggest a mixing of spin states at Landau level coincidence. We propose that the level repulsion is due to the presence of spin-orbit and of band-non-parabolicity terms which are relevant in narrow-gap systems. Furthermore, electron-electron interaction is significant in our structure, as demonstrated by the large values of the interaction-induced enhancement of the electronic g-factor.