Orbital ordering in the two-dimensional ferromagnetic semiconductor Rb_2CrCl_4

TL;DR

This study uses density functional theory to analyze the electronic and magnetic properties of the 2D ferromagnetic semiconductor Rb_2CrCl_4, revealing its semiconducting nature, magnetic order, and sensitivity of its optical gap to structural changes.

Contribution

First-principles calculations elucidate the electronic structure and magnetic behavior of Rb_2CrCl_4, highlighting the impact of structural distortions on its optical properties.

Findings

Rb_2CrCl_4 is a semiconductor with ferromagnetic order.

Magnetic properties are robust against Jahn-Teller structural changes.

Optical band gap is highly responsive to structural modifications.

Abstract

We present the results of electronic structure calculations for the two-dimensional ferromagnet Rb_2CrCl_4. They are obtained by the augmented spherical wave method as based on density functional theory and the local density approximation. In agreement with experimental data Rb_2CrCl_4 is found to be semiconducting and displays long-range ferromagnetic order of the localized Cr 3d moments. The magnetic properties are almost independent of the structural modifications arising from the Jahn-Teller instability, which leads from the parent body-centered tetragonal K_2NiF_4 structure to a side-centered orthorhombic lattice. In contrast, our calculations give evidence for a strong response of the optical band gap to the corresponding structural changes.