Brightened Optical Transition Hinting to Strong Spin‐Lattice Coupling in a Layered Antiferromagnet
Volodymyr Multian, Fan Wu, D. van der Marel, Nicolas Ubrig, J. Teyssier
Abstract
Abstract Two‐dimensional (2D) van der Waals magnets show strong interconnection between their electrical, magnetic, and structural properties. Here, the emergence of a luminescent transition is revealed upon crossing the Néel transition temperature of CrPS 4 , a layered antiferromagnetic semiconductor. This luminescent transition occurs above the lowest absorption level. The optical transitions are attributed to excited states of the t 2g orbitals of the Cr 3+ ions, which are influenced by the distortion of the octahedral crystal field. Specifically, the vicinity of the Néel temperature, the distortion switches from an anti‐polar to a polar arrangement, thereby not only promoting an additional luminescent pathway but also significantly strengthening the static dipole moment detected by a marked enhancement in the intensity of the second harmonic generation. These results strongly encourage further investigation into the multiferroic properties and potential coupling mechanisms in CrPS 4 .