Switching 2D Magnetic States via Pressure Tuning of Layer Stacking

TL;DR

This study demonstrates that applying hydrostatic pressure to 2D CrI3 crystals can significantly alter their magnetic states by changing stacking arrangements, enabling control over magnetic phases for potential device applications.

Contribution

It provides experimental evidence that pressure can tune magnetic order in 2D magnets by modifying stacking configurations, revealing a new method for magnetic phase control.

Findings

Interlayer magnetic coupling more than doubled under pressure

Pressure induces a transition from antiferromagnetic to ferromagnetic in bilayer CrI3

Coexistence of multiple magnetic phases observed in trilayer CrI3

Abstract

The physical properties of two-dimensional van der Waals (2D vdW) crystals depend sensitively on the interlayer coupling, which is intimately connected to the stacking arrangement and the interlayer spacing. For example, simply changing the twist angle between graphene layers can induce a variety of correlated electronic phases, which can be controlled further in a continuous manner by applying hydrostatic pressure to decrease the interlayer spacing. In the recently discovered 2D magnets, theory suggests that the interlayer exchange coupling strongly depends on layer separation, while the stacking arrangement can even change the sign of the magnetic exchange, thus drastically modifying the ground state. Here, we demonstrate pressure tuning of magnetic order in the 2D magnet CrI3. We probe the magnetic states using tunneling and scanning magnetic circular dichroism microscopy measurements. We find that the interlayer magnetic coupling can be more than doubled by hydrostatic pressure. In bilayer CrI3, pressure induces a transition from layered antiferromagnetic to ferromagnetic phases. In trilayer CrI3, pressure can create coexisting domains of three phases, one ferromagnetic and two distinct antiferromagnetic. The observed changes in magnetic order can be explained by changes in the stacking arrangement. Such coupling between stacking order and magnetism provides ample opportunities for designer magnetic phases and functionalities.