Mott insulating phase and coherent-incoherent crossover across magnetic phase transition in 2D antiferromagnetic CrSBr

TL;DR

This study reveals that 2D antiferromagnetic CrSBr is a Mott insulator, exhibiting a coherent-incoherent crossover across its magnetic phase transition, highlighting the complex interplay between electron correlation and magnetic order.

Contribution

It provides the first experimental and theoretical evidence of Mott insulating behavior and band reconfiguration in CrSBr across magnetic phases.

Findings

CrSBr is confirmed as a Mott insulator.

Band structure reconfigures across magnetic transition.

Coherent-incoherent crossover occurs with magnetic order dissolution.

Abstract

In two-dimensional van der Waals magnetic materials, the interplay between magnetism and electron correlation can give rise to new ground states and lead to novel transport and optical properties. A fundamental question in these materials is how the electron correlation manifests and interacts with the magnetic orders. In this study, we demonstrate that the recently discovered 2D antiferromagnetic material, CrSBr, is a Mott insulator, through the combined use of resonant and temperature-dependent angle-resolved photoemission spectroscopy techiniques, supplemented by dynamical mean-field theory analysis. Intriguingly, we found that as the system transitions from the antiferromagnetic to the paramagnetic phases, its Mott bands undergo a reconfiguration, and a coherent-incoherent crossover, driven by the dissolution of the magnetic order. Our findings reveal a distinctive evolution of band structure associated with magnetic phase transitions, shedding light on the investigation of intricate interplay between correlation and magnetic orders in strongly correlated van der Waals magnetic materials.