Electronic and magnetic properties of X-doped (X = Ti, Zr, Hf) tungsten disulphide monolayer

Based on density functional theory, we investigated electronic and magnetic properties of X-doped (Group 4) WS2 monolayer for 6.25% and 12.5% X concentration. Numerical results show that one X-doped WS2 monolayer is non-magnetic, while two X-doped systems of the next nearest neighbor configuration are ferromagnetic (FM). The hybridization between the X dopant and its neighboring W and S atoms results in the splitting of the energy levels near the Fermi energy. These results suggest the p(d)-d(d) hybridization mechanism for the magnetism of the X-doped WS2 monolayer structures. The asymmetric charge density distribution induces to magnetism for two next nearest neighbor X-doped WS2 systems. The studies find that the two next nearest X-doped WS2 monolayers to be candidates for magnetic metallic material. Moreover, the formation energy calculations also indicate that it is energy favorably and relatively easier to incorporate X atom into the WS2 monolayer under S-rich experimental conditions. Our results show that substitutional doping from IVB group is an effective way to modulate electronic and magnetic properties of tungsten disulphide monolayer. (C) 2015 Elsevier B.V. All rights reserved.