Electrically tunable room-temperature ferromagnetism in CrBr$_3$

TL;DR

This study demonstrates that applying gate-induced charge doping can significantly enhance and control room-temperature ferromagnetism in monolayer CrBr3, opening new avenues for spintronic devices.

Contribution

It reveals electrically tunable room-temperature ferromagnetism in monolayer CrBr3 through first-principles modeling, showing how doping modulates magnetic interactions.

Findings

Ferromagnetism persists up to room temperature with hole doping.

Electron doping switches magnetic easy axis.

Magnetic properties are controllable via gate voltage.

Abstract

The recent discovery of magnetic ordering in two-dimension has lead to colossal efforts to find atomically thin materials that order at high temperatures. However, due to fundamental spin fluctuation in reduced dimension, the room-temperature ferromagnetism remains elusive. Here, we report a dramatic manipulation of magnetic ordering up to room temperature in the monolayer CrBr$_3$, within the first-principles Heisenberg XXZ model. The exchange and anisotropic magnetic interactions are externally modulated by a gate-induced charge carrier doping that triggers a nontrivial phase diagram. High-temperature ferromagnetism is associated with a substantial increase in both effective ferromagnetic exchange and overall magnetic anisotropy under experimentally attainable hole doping. In contrast, electron doping quickly switches the magnetic easy axis. The gate-tuneable room temperature ferromagnetism in CrBr$_3$ presents new possibilities in electrically controlled spintronic and magnetoelectric devices based on atomically thin crystals.