Cr_xMn_1-xSbSe₃—A Quasi-One-Dimensional van der Waals Magnet

A van der Waals (vdW) material is characterized by the presence of low-dimensional charge neutral units that exhibit strong covalent bonding within the units and weak van der Waals interaction between the units. The recent discovery of magnetic ordering in low-dimensional vdW materials has garnered considerable interest. Both two-dimensional and quasi-one-dimensional vdW magnets have been reported.<br/><br/>In this study, we employed first-principles density functional theory (DFT) to investigate the composition-dependent structure-property relationship of Cr_xMn_1-xSbSe₃, a quasi-one-dimensional vdW magnet. The concentration of Mn is found to have strong effects on the electronic structure and magnetic properties of the system. Using the exchange coupling parameters between magnetic atoms obtained from DFT, in conjunction with Monte Carlo method for spin dynamics, we estimated the Curie temperature of this material to understand its thermodynamic stability. For CrSbSe₃, our calculated Curie temperature is shown to be in good agreement with the experimental value of ~70 K. Our results further reveal a stable phonon dispersion and a narrow band gap with distinct energy bands for the majority and minority spins, confirming CrSbSe₃ as a ferromagnetic semiconductor at low temperatures.