# Dielectric tunability of magnetic properties in orthorhombic ferromagnetic monolayer CrSBr

## TL;DR

This study investigates how dielectric screening influences the magnetic properties of monolayer CrSBr, revealing tunable anisotropy and magnetic ordering, and highlighting its potential for substrate-controlled magnetic applications.

## Contribution

The paper combines Green's function formalism with first-principles calculations to analyze dielectric screening effects on 2D CrSBr's magnetic properties, a novel approach for this material.

## Key findings

- Magnetic anisotropy depends strongly on Coulomb interaction and dielectric environment.
- Free-standing CrSBr is near an easy-plane magnet with suppressed long-range order.
- Large external screening stabilizes easy-axis ferromagnetic order.

## Abstract

Monolayer CrSBr is a recently discovered semiconducting spin-3/2 ferromagnet with a Curie temperature around 146 K. Unlike many other known two-dimensional (2D) magnets, CrSBr has an orthorhombic lattice, giving rise, for instance, to spatial anisotropy of the magnetic excitations within the 2D plane. Theoretical description of CrSBr within a spin Hamiltonian approach turns out to be nontrivial due to the triaxial magnetic anisotropy as well as due to magnetic dipolar interactions, comparable to spin-orbit effects in CrSBr. Here, we employ a Green's function formalism combined with first-principles calculations to systematically study the magnetic properties of monolayer CrSBr in different regimes of surrounding dielectric screening. We find that the magnetic anisotropy and thermodynamical properties of CrSBr depend significantly on the Coulomb interaction and its external screening. In the free-standing limit, the system turns out to be close to an easy-plane magnet, whose long-range ordering is partially suppressed. On the contrary, in the regime of large external screening, monolayer CrSBr behaves like an easy-axis ferromagnet with more stable magnetic ordering. Despite being relatively large, the magnetic dipolar interactions have only little effect on the magnetic properties. Our findings suggests that 2D CrSBr is suitable platform for studying the effects of substrate screening on magnetic ordering in low dimensions.