Layer Dependent MCD on Van der Waal-like 2D ferromagnetism*

The layered ferromagnetic semiconductor CrSiTe₃ is a promising candidate for spintronic applications. According to DFT calculations, its bulk bandgap is predicted to be ~0.4 eV; meanwhile, a Curie temperature of ~33 K was reported, thus providing evidence for bulk ferromagnetism. More importantly, due to the van der Waal-like interlayer coupling, CrSiTe₃ is exfoliable and possible to achieve monolayers through mechanical exfoliation making it appealing for 2D spintronics. However, the fundamental properties of CrSiTe₃ have not been thoroughly studied, particularly in the few layers limit. . A number of of theoretical reports, suggest that the monolayer could have a larger bandgap but the presence of magnetism is still debatable (FM or AFM order). Nonetheless, among these predictions, the common agreement is that the decisive factor causing FM- or AFM-exchange coupling is the distance between Cr-Te-Cr bonds, which indicates that the spin configuration is closely related to the lattice. Therefore, In order to study the presence of magnetism and to understand the role spin-phonon interaction, we performed layer-dependent magnetization measurements via the magnetic circular dichroism (MCD) and Raman spectroscopy at different Ts.