Accurate computations of Rashba spin-orbit coupling in interacting systems: from the Fermi gas to real materials

TL;DR

This paper develops a quantum Monte Carlo method to accurately compute Rashba spin-orbit coupling effects in interacting fermion systems, covering from Fermi gases to real materials with strong correlations.

Contribution

It introduces a novel approach within auxiliary-field quantum Monte Carlo to handle Rashba SOC in interacting systems, enabling predictive studies of complex materials.

Findings

Exact ground-state calculations for 2D Fermi gas with SOC

Benchmark results for Hubbard model with SOC

Method enables study of SOC and strong correlations in materials

Abstract

We describe the treatment of Rashba spin-orbit coupling (SOC) in interacting many-fermion systems within the auxiliary-field quantum Monte Carlo framework, and present a set of illustrative results. These include numerically exact calculations on the ground-state properties of the spin-balanced, attractive two-dimensional Fermi gas, as well as a study of a tight-binding Hamiltonian with repulsive interaction. These systems are formally connected via the Hubbard Hamiltonian with SOC, but cover different physics ranging from superfluidity and triplet pairing to SOC in real materials in the presence of strong interactions in localized orbitals. We carry out detailed benchmark studies of the method in the latter case when an approximation is needed to control the sign problem for repulsive Coulomb interactions. The methods presented here provide an approach for predictive computations in materials to study the interplay of SOC and strong correlation.