Correlation Effects in van der Waals CrXTe₃ Materials (X: Si, Ge) from X-ray Spectroscopy Studies

The recently discovered CrXTe3 (X: Si, Ge) layered ferromagnets are under increased attention for the demonstration of low-dimensional ferromagnetism down to the monolayer limit. In the present study, we employ near-edge X-ray absorption fine structure spectroscopy (NEXAFS) and resonant photoelectron spectroscopy (ResPES) at the Cr L2,3 absorption edge accompanied by DFT calculations to gain insights into the electronic structure and electron correlation effects for these compounds. It is found that the 3dn–1 final state in the photoemission spectra is located at the top of the valence band, thus assigning CrXTe3 to the Mott–Hubbard state. Moreover, as revealed in NEXAFS and ResPES, significant hybridization between Cr 3d and Te 5p valence band states is found in both compounds, leading to the slightly weaker electron localization in CrGeTe3 as compared to CrSiTe3. Our results bring new insight into the deep understanding of the correlation phenomena in these vdW materials allowing us to draw further ways on the modulation of the correlation effects and magnetic structures in different layered compounds.