# Topological Charge/spin density Wave in InAs/GaSb Quantum Wells under an In-plane Magnetic Field

## TL;DR

This paper investigates the effects of interactions and magnetic fields on InAs/GaSb quantum wells, revealing novel topological phases and the renormalization of the g-factor that influences edge transport.

## Contribution

It introduces a phase diagram showing interaction-induced topological and trivial phases, including a charge/spin density wave and an exciton condensate, under an in-plane magnetic field.

## Key findings

- Identification of a topologically non-trivial charge/spin density wave phase.
- Discovery of a topologically trivial exciton condensate phase.
- Renormalization of the g-factor due to interactions, stabilizing edge transport.

## Abstract

We study interaction effect of quantum spin Hall state in InAs/GaSb quantum wells under an in-plane magnetic field by using the self-consistent mean field theory. We construct a phase diagram as a function of intra-layer and inter-layer interactions, and identify two novel phases, a charge/spin density wave phase and an exciton condensate phase. The charge/spin density wave phase is topologically non-trivial with helical edge transport at the boundary, while the exciton condensate phase is topologically trivial. The Zeeman effect is strongly renormalized due to interaction in certain parameter regimes of the system, leading to a much smaller g-factor, which may stabilize the helical edge transport.