Magnetism and metal-insulator transitions in the Rashba-Hubbard model

TL;DR

This paper investigates how Rashba spin-orbit coupling influences magnetic and metal-insulator transitions in the Hubbard model on a square lattice, revealing a sequence of phases and the emergence of magnetic stripes due to spin-orbit effects.

Contribution

It introduces a Hartree-Fock analysis of the Rashba-Hubbard model, uncovering new transition sequences and magnetic phases driven by spin-orbit coupling in quasi-2D systems.

Findings

Sequence of transitions: Mott insulator to metallic antiferromagnet to Rashba metal

Rashba coupling promotes magnetic striped phases in doped regimes

Spectral analysis links magnetic rearrangements to spin-orbit induced chirality

Abstract

The nature of metal-insulator and magnetic transitions is still a subject under intense debate in condensed matter physics. Amongst the many possible mechanisms, the interplay between electronic correlations and spin-orbit couplings is an issue of a great deal of interest, in particular when dealing with quasi-2D compounds. In view of this, here we use a Hartree-Fock approach to investigate how the Rashba spin-orbit coupling, $V_\text{SO}$, affects the magnetic ordering provided by a Hubbard interaction, $U$, on a square lattice. At half-filling, we have found a sequence of transitions for increasing $V_\text{SO}$: from a Mott insulator to a metallic antiferromagnet, and then to a paramagnetic Rashba metal. Also, our results indicate that the Rashba coupling favors magnetic striped phases in the doped regime. By analyzing spectral properties, we associate the rearrangement of the magnetic ordering with the emerging chirality created by the spin-orbit coupling. Our findings provide insights towards clarifying the competition between these tendencies.