Quantum Spin Hall Insulators with Interactions and Lattice Anisotropy

TL;DR

This paper explores how spin-orbit coupling, electron interactions, and lattice anisotropy influence quantum spin Hall insulators, revealing phase stability, edge state evolution, and the emergence of a quantum spin liquid phase.

Contribution

It provides a comprehensive analysis of the phase diagram and stability of quantum spin Hall phases under interactions and anisotropy using advanced theoretical methods.

Findings

Quantum spin Hall phase stability depends on interaction strength and anisotropy.

Edge states evolve significantly with Hubbard interactions and lattice anisotropy.

A quantum spin liquid phase exists at weak spin-orbit coupling and intermediate interactions.

Abstract

We investigate the interplay between spin-orbit coupling and electron-electron interactions on the honeycomb lattice combining the cellular dynamical mean-field theory and its real space extension with analytical approaches. We provide a thorough analysis of the phase diagram and temperature effects at weak spin-orbit coupling. We systematically discuss the stability of the quantum spin Hall phase toward interactions and lattice anisotropy resulting in the plaquette-honeycomb model. We also show the evolution of the helical edge states characteristic of quantum spin Hall insulators as a function of Hubbard interaction and anisotropy. At very weak spin-orbit coupling and intermediate electron-electron interactions, we substantiate the existence of a quantum spin liquid phase.