High Curie temperature in magnetically doped tungsten diselenide

Two-dimensional (2D) magnets have attracted immense attention recently because of their possible use in future energy-efficient spintronic devices. A class of 2D magnetic materials are transition-metal dichalcogenides (TMDs) that are substitutionally doped with magnetic transition metals like Cr, Fe, and Mn. Especially, TMDs based on heavy elements like tungsten (W) and selenium (Se). In this work, we investigate magnetism in magnetically doped WSe₂ monolayers using Density Functional Theory (DFT). In particular, we simulate the magnetic phase transition using Monte-Carlo simulations of a classical Heisenberg Hamiltonian, built for randomly doped samples of WSe₂. Specifically, we investigate the effect of dopant-atom clustering on the magnetic properties of doped monolayer WSe₂. To take into account the effect of the clustering of the dopant atoms, we introduce a functional form for the exchange interaction and obtain the parameters of our classical Heisenberg Hamiltonian from total energy DFT calculations. From the Monte-Carlo calculations, we extract the doping-density-dependent Curie temperature for each dopant atom. Finally, we show a high Curie temperature of about 300 K in Fe/Mn-doped WSe₂ at a doping concentration of 7-8%.