Fluctuation-driven insulator-to-metal transition in an external magnetic field

TL;DR

This paper investigates how an external magnetic field influences a correlated electron system, revealing a first-order insulator-to-metal transition driven by collective fluctuations and coexistence of phases.

Contribution

It introduces a model showing a broad parameter region with coexisting metallic and insulating solutions, highlighting the role of collective fluctuations in the transition.

Findings

Coexistence of metallic and insulating solutions in a broad parameter range

First-order insulator-to-metal transition driven by collective fluctuations

Global instability of the saturated magnetic state precedes local instabilities

Abstract

We consider a model for a metal-insulator transition of correlated electrons in an external magnetic field. We find a broad region in interaction and magnetic field where metallic and insulating (fully magnetized) solutions coexist and the system undergoes a first-order metal-insulator transition. A global instability of the magnetically saturated solution precedes the local ones and is caused by collective fluctuations due to poles in electron-hole vertex functions.