Direct Optical Probing of the Magnetic Properties of the Layered Antiferromagnet CrPS$_4$

TL;DR

This study demonstrates an all-optical method to directly measure magnetic properties of CrPS4, linking magnetic and optical behaviors, supported by experiments and density functional theory calculations, advancing understanding of layered antiferromagnets.

Contribution

It introduces a novel optical approach to probe magnetic properties in layered antiferromagnets, validated by experiments and theoretical modeling, suitable for ultra-thin samples.

Findings

Circular polarization degree of photoluminescence measures net magnetization.

Raman scattering reveals magnetic susceptibility and spin ordering.

Density functional theory explains spectral shifts related to magnetic states.

Abstract

Unusual magnetic properties of Van der Waals type antiferromagnetic semiconductors make them highly attractive for spintronics and optoelectronics. A link between the magnetic and optical properties of those materials, required for practical applications, has not been, however, established so far. Here, we report on a combined experimental and theoretical study of magnetic, optical, and structural properties of bulk CrPS$_{4}$ samples. We find that the magnetic-field-dependent circular polarization degree of the photoluminescence is a direct measure of the net magnetization of CrPS$_{4}$. Complementary, Raman scattering measured as a function of magnetic field and temperature enables the determination of the magnetic susceptibility curve of the material. Our experimental results are backed by Our experimental results are supported by density functional theory calculations that take as input the lattice parameters determined from temperature-dependent X-ray diffraction measurements. This allows us to explain the impact of spin ordering on the spectral position of Raman transitions in CrPS$_4$, as well as anomalous temperature shifts of selected of them. The presented method for all-optical determination of the magnetic properties is highly promising for studies of spin ordering and magnetic phase transitions in single- or a few-layer samples of magnetic layered materials, for which a poor signal-to-noise ratio precludes any reliable neutron scattering or magnetometry measurements.