Strong Spin-Phonon Coupling in Two-Dimensional Magnetic Semiconductor CrSBr

Abstract

Recently, spin-phonon coupling (SPC) has gained considerable attention especially in two-dimensional (2D) materials. Herein, density-functional theory is used to investigate the SPC effect in CrSBr, a recently fabricated 2D magnetic semiconductor. It is found that the phonon vibrations are strongly dependent on the spin ordering. The breaking of magnetic symmetry changes phonon spectrum dependency obviously. In particular, the SPC constant is found to be 20.2 cm–1, which is one order of magnitude larger than that of most other 2D materials. The group velocity and Grüneisen constant in the ferromagnetic (FM) state are increased by ∼23 and ∼16% than that in the antiferromagnetic state. Furthermore, the thermal conductivity is enhanced by ∼43% for FM spin ordering because of stronger lattice anharmonicity. The Curie temperature of the system can be tuned ∼30% by lattice deformation because of the strong SPC. Our work provides fundamental insights into the SPC effect on the CrSBr monolayer and sheds light on its potential for novel spintronic application