Oral: First-principles investigation of the electronic structure and magnetic properties of a van der Waals magnet.

Van der Waals (vdW) materials consist of low-dimensional, charge-neutral units with strong covalent bonds within the units and weak van der Waals interactions between them. Recent findings of magnetic ordering in these materials have heightened interest, with both two-dimensional and quasi-one-dimensional vdW magnets being reported. In our study, we utilized first-principles density functional theory (DFT) to explore the composition-dependent structure-property relationship in Cr_xMn_1-xSbSe₃ (x=0, 0.5, 1), a quasi-one-dimensional vdW magnet. By combining DFT-derived exchange coupling parameters with Monte Carlo simulations for spin dynamics, we estimated the Curie temperature, providing insights into the material's thermodynamic stability. Our calculated electronic structure, magnetic properties, and Curie temperature for CrSbSe₃ are found to be in good agreement with experimental results, confirming it as a ferromagnetic semiconductor with a Curie temperature of approximately ~65K. Furthermore, we find that the concentration of Mn in Cr_xMn_1-xSbSe₃ significantly influences the system's electronic structure and magnetic properties, accompanied by a decrease in the Curie temperature with an increase in concentration.