Topological phase transitions between chiral and helical spin textures in a lattice with spin-orbit coupling and a magnetic field

TL;DR

This paper explores how spin-orbit coupling and magnetic fields in a 2D honeycomb lattice induce topological phase transitions, enabling control over spin textures and potential quantum spin manipulation.

Contribution

It demonstrates the transition between helical and chiral topological phases and shows how spin orientation can be tuned via Rashba coupling in a lattice system.

Findings

Spin-orbit coupling induces topological phase transitions.

Edge state spin orientation can be tuned by Rashba coupling.

Potential realization in cold atom systems with engineered fields.

Abstract

We consider the combined effects of large spin-orbit couplings and a perpendicular magnetic field in a 2D honeycomb fermionic lattice. This system provides an elegant setup to generate versatile spin textures propagating along the edge of a sample. The spin-orbit coupling is shown to induce topological phase transitions between a helical quantum spin Hall phase and a chiral spin-imbalanced quantum Hall state. Besides, we find that the spin orientation of a single topological edge state can be tuned by a Rashba spin-orbit coupling, opening an interesting route towards quantum spin manipulation. We discuss the possible realization of our results using cold atoms trapped in optical lattices, where large synthetic magnetic fields and spin-orbit couplings can be engineered and finely tuned. In particular, this system would lead to the observation of a time-reversal-symmetry-broken quantum spin Hall phase.