Strain and Correlation Modulated Magnetic Anisotropy and Dzyaloshinskii--Moriya Interaction in 2D H-FeTe$_2$

TL;DR

This study reveals that monolayer H-FeTe2 naturally exhibits strong, tunable Dzyaloshinskii--Moriya interaction and magnetic anisotropy due to its intrinsic properties, with strain and electron correlation significantly influencing these magnetic features.

Contribution

It demonstrates that pristine 2D H-FeTe2 inherently hosts robust DMI and magnetic anisotropy, with their properties tunable by strain and electron correlation, unlike previous approaches requiring doping or heterostructures.

Findings

Non-monotonic strain dependence of MAE and DMI.

Strain-tunable crossover between in-plane and out-of-plane easy axes.

Enhanced in-plane DMI under combined strain and correlation.

Abstract

In the ongoing research on two-dimensional (2D) ferromagnetic materials with strong intrinsic Dzyaloshinskii--Moriya interaction (DMI), most efforts have focused on doping, Janus engineering, or heterostructure formation to break inversion symmetry and enhance spin--orbit coupling (SOC). Here, we demonstrate that a pristine 2D material, monolayer H-FeTe$_2$, can naturally host robust DMI and magnetic anisotropy due to its intrinsic broken inversion symmetry and the strong SOC of Te atoms. We explore the effect of biaxial strain and electron correlation on H-FeTe$_2$ using first-principles DFT+$U$ calculations. We systematically investigate the Heisenberg exchange interaction, magnetic anisotropy, and DMI in the space spanned by strain and correlation. Our results reveal a distinct, non-monotonic strain dependence of both magnetic anisotropy energy (MAE) and DMI, including a strain-tunable crossover between in-plane and out-of-plane magnetic easy axes. A remarkable enhancement of the in-plane DMI is observed under the combined influence of strain and strong correlations, which is unusual for pristine 2D materials and suggests a favorable regime for spintronic applications.Notably, even in the absence of strain, H-FeTe$_2$ exhibits finite DMI and considerable anisotropy, which is rare for a pure 2D material. Through these findings, we present H-FeTe$_2$ as a unique pristine 2D system with robust and tunable spin interactions for exploring fundamental spin--orbit-driven magnetic phenomena.