Point defects in two-dimensional high-entropy transition metal dichalcogenides: The effect of local chemical environments

Recently, two-dimensional (2D) high-entropy transition metal dichalcogenides (TMDCs), which combine the characteristics of high-entropy and 2D materials, have been successfully synthesized in experiments and garnered considerable attention. However, research on point defects in 2D high-entropy TMDCs remains limited. Therefore, we focus on investigating the structure and formation energy of the common point defects of the 2D high-entropy $(\mathrm{WMoNbTaV}){\mathrm{S}}_{2}$ monolayer using first-principles calculations. By comparing the low-, medium-, and high-entropy TMDC materials, we found that among the point defects, the single sulfur vacancy $({\mathrm{V}}_{\mathrm{S}1})$ and S-M antisite defects $({\mathrm{S}}_{\mathrm{M}})$ with relatively small defect formation energies are most easily formed. From a single ordered structure to a multicomponent disordered structure, the distribution of defect formation energies broadens, especially for the five-component $(\mathrm{WMoNbTaV}){\mathrm{S}}_{2}$ monolayer. This is caused by the increase in the types of metallic elements, which leads to a greater complexity in the local chemical environments around the defects. Further examination of the effects of local chemical environments on vacancy formation energies revealed a correlation between the vacancy formation energies of multicomponent 2D TMDCs and those of their single-component counterparts. This study elucidates the influence of local chemical environments on the point defect properties of 2D high-entropy TMDCs, offering new insights and strategies for controlling defect generation in these systems.