Controlling magnetism in 2D CrI3 by electrostatic doping

TL;DR

This paper demonstrates electrical control of magnetism in 2D CrI3 materials through electrostatic doping, enabling tunable magnetic properties and phase transitions in monolayer and bilayer structures.

Contribution

It introduces a dual-gate device to modulate magnetic order in 2D CrI3, revealing doping-dependent magnetic phase transitions and switching capabilities.

Findings

Doping alters saturation magnetization, coercive force, and Curie temperature in monolayer CrI3.

Doping induces a transition from antiferromagnetic to ferromagnetic order in bilayer CrI3.

Small gate voltages can robustly switch magnetization states in bilayer CrI3.

Abstract

The atomic thickness of two-dimensional (2D) materials provides a unique opportunity to control material properties and engineer new functionalities by electrostatic doping. Electrostatic doping has been demonstrated to tune the electrical and optical properties of 2D materials in a wide range, as well as to drive the electronic phase transitions. The recent discovery of atomically thin magnetic insulators has opened up the prospect of electrical control of magnetism and new devices with unprecedented performance. Here we demonstrate control of the magnetic properties of monolayer and bilayer CrI3 by electrostatic doping using a dual-gate field-effect device structure. In monolayer CrI3, doping significantly modifies the saturation magnetization, coercive force and Curie temperature, showing strengthened (weakened) magnetic order with hole (electron) doping. Remarkably, in bilayer CrI3 doping drastically changes the interlayer magnetic order, causing a transition from an antiferromagnetic ground state in the pristine form to a ferromagnetic ground state above a critical electron density. The result reveals a strongly doping-dependent interlayer exchange coupling, which enables robust switching of magnetization in bilayer CrI3 by small gate voltages.