Variational study of the nu=1 quantum Hall ferromagnet in the presence of spin-orbit interaction

TL;DR

This study explores how spin-orbit interactions affect the stability and spin polarization of the nu=1 quantum Hall ferromagnet, revealing new phase behaviors and stability conditions.

Contribution

It introduces a variational approach to analyze the impact of Rashba and Dresselhaus spin-orbit coupling on the quantum Hall ferromagnet, showing new phase diagrams.

Findings

Fully spin-polarized state is unstable with Rashba or Dresselhaus coupling when q*g>0.

Alternative states with in-plane spin components become energetically favorable at strong spin-orbit interaction.

The phase diagram differs qualitatively from previous models.

Abstract

We investigate the nu=1 quantum Hall ferromagnet in the presence of spin-orbit coupling of the Rashba or Dresselhaus type by means of Hartree-Fock-typed variational states. In the presence of Rashba (Dresselhaus) spin-orbit coupling the fully spin-polarized quantum Hall state is always unstable resulting in a reduction of the spin polarization if the product of the particle charge $q$ and the effective $g$-factor is positive (negative). In all other cases an alternative variational state with O(2) symmetry and finite in-plane spin components is lower in energy than the fully spin-polarized state for large enough spin-orbit interaction. The phase diagram resulting from these considerations differs qualitatively from earlier studies.