Electronic Liquid Crystalline Phases in a Spin-Orbit Coupled Two-Dimensional Electron Gas

TL;DR

This paper explores various liquid crystalline and Wigner crystalline phases in a two-dimensional electron gas with Rashba spin-orbit coupling, highlighting how interactions and density influence the ground state and phase transitions.

Contribution

It identifies possible ground states, including anisotropic Wigner crystals, smectic, and nematic phases, in a spin-orbit coupled 2D electron gas at low densities, with analysis of phase melting mechanisms.

Findings

Anisotropic Wigner crystal becomes more anisotropic at lower densities.

Stripe and smectic phases are energetically favorable under certain conditions.

Thermal and quantum fluctuations can induce a non-magnetic nematic phase.

Abstract

We argue that the ground state of a two-dimensional electron gas with Rashba spin-orbit coupling realizes one of several possible liquid crystalline or Wigner crystalline phases in the low-density limit, even for short-range repulsive electron-electron interactions (which decay with distance with a power larger than 2). Depending on specifics of the interactions, preferred ground-states include an anisotropic Wigner crystal with an increasingly anisotropic unit cell as the density decreases, a striped or electron smectic phase, and a ferromagnetic phase which strongly breaks the lattice point-group symmetry, i.e. exhibits nematic order. Melting of the anisotropic Wigner crystal or the smectic phase by thermal or quantum fluctuations can gives rise to a non-magnetic nematic phase which preserves time-reversal symmetry.