Emergence of Quantum Nonmagnetic Insulating Phase in Spin-Orbit Coupled Square Lattices

TL;DR

This paper explores how spin-orbit coupling influences the metal-insulator transition in a square lattice Hubbard model, revealing a nonmagnetic insulating phase with potential algebraic spin-liquid characteristics.

Contribution

It uncovers a novel nonmagnetic insulating phase induced by spin-orbit coupling near the Mott transition, confirmed through cluster dynamical mean-field theory.

Findings

Discovery of a nonmagnetic insulating phase with a finite gap

Power-law scaling of spin correlations suggests algebraic spin-liquid behavior

Confirmation of results using non-perturbative cluster dynamical mean-field theory

Abstract

We investigate the metal-insulator transition (MIT) and phase diagram of the half-filled Fermi Hubbard model with Rashba-type spin-orbit coupling (SOC) on a square optical lattice. The interplay between the atomic interactions and SOC results in distinctive features of the MIT. Significantly, in addition to the diverse spin ordered phases, a nonmagnetic insulating phase emerges in a considerably large regime of parameters near the Mott transition. This phase has a finite single-particle gap but vanishing magnetization and spin correlation exhibits a power-law scaling, suggesting a potential algebraic spin-liquid ground state. These results are confirmed by the non-perturbative cluster dynamical mean-field theory.