First-order magnetic phase-transition of mobile electrons in monolayer MoS$_2$

TL;DR

This paper reports the discovery of a first-order magnetic phase transition in monolayer MoS$_2$, controlled by gate voltage, with abrupt optical and electronic property changes indicating a switch between ferromagnetic and paramagnetic phases.

Contribution

It provides experimental evidence of a gate-controlled first-order magnetic phase transition in monolayer MoS$_2$, revealing new insights into 2D magnetic phenomena.

Findings

Abrupt optical response change at phase boundary

Large variation in electron effective mass

Magnetic order controlled by gate voltage

Abstract

Evidence is presented for a first-order magnetic phase transition in a gated two-dimensional semiconductor, monolayer-MoS$_2$. The phase boundary separates a spin-polarised (ferromagnetic) phase at low electron density and a paramagnetic phase at high electron density. Abrupt changes in the optical response signal an abrupt change in the magnetism. The magnetic order is thereby controlled via the voltage applied to the gate electrode of the device. Accompanying the change in magnetism is a large change in the electron effective mass.