Phase diagram of the interacting persistent spin-helix state

Hong Liu, Weizhe Edward Liu, Stefano Chesi, Robert Joynt, Dimitrie Culcer

Research output: Contribution to journalArticleResearchpeer-review

Abstract

We study the phase diagram of the interacting two-dimensional electron gas (2DEG) with equal Rashba and Dresselhaus spin-orbit coupling, which for weak coupling gives rise to the well-known persistent spin-helix phase. We construct the full Hartree-Fock phase diagram using a classical Monte Carlo method analogous to that used in Phys. Rev. B 96, 235425 (2017)10.1103/PhysRevB.96.235425. For the 2DEG with only Rashba spin-orbit coupling, it was found that at intermediate values of the Wigner-Seitz radius rs the system is characterized by a single Fermi surface with an out-of-plane spin polarization, whereas at slightly larger values of rs it undergoes a transition to a state with a shifted Fermi surface and an in-plane spin polarization. The various phase transitions are first order, and this shows up in discontinuities in the conductivity, and the appearance of anisotropic resistance in the in-plane polarized phase. In this paper we show that the out-of-plane spin-polarized region shrinks as the strength of the Dresselhaus spin-orbit interaction increases and entirely vanishes when the Rashba and Dresselhaus spin-orbit coupling strengths are equal. At this point the system can be mapped onto a 2DEG without spin-orbit coupling, and this transformation reveals the existence of an in-plane spin-polarized phase with a single displaced Fermi surface beyond rs>2.01. This is confirmed by classical Monte Carlo simulations. We discuss experimental observation and useful applications of the novel phase as well as caveats of using the classical Monte Carlo method.

Original languageEnglish
Article number205410
Number of pages11
JournalPhysical Review B
Volume102
Issue number20
DOIs
Publication statusPublished - 10 Nov 2020

Cite this