First-principles Study Of MoS₂-WS₂and MoS₂-MoTe₂Monolayer Heterostructures And Fe Doped Monolayer MoS₂

MoS2mono layer is a relatively new class of two-dimensional materials. Due to its unique properties MoS2mono layer has been intensively studied theoretically and experimentally. It has many potential implications in the fields of field-effect-transistor, catalyst, photoelectronic devices and spinelectronic devices. So to focus on the study of MoS2monolayer is very important.Using first-principles calculations, we systematically studied the different properties of MoS2-WS2and MoS2-MoTe2monolayer heterostructures and Fe doped monolayer MoS2. By optimizing the structure of the heterostructue and Fe doped MoS2, we calculated the corresponding electronic structure and magnetic properties of the different systems. Then we analyzed the results and modifications of the doping systems. The main contents are as followed:(1) We systematically studied the geometric and electronic structure of MoS2-WS2and MoS2-MoTe2monolayer heterostructues. Analysis of the variation of the total density of states (TDOS) and partial density of states (PDOS) of the specific atoms in the interfaces demonstrates that the two heterostructures show rather different properties and different changes from the initial MoS2monolayer. The MoS2-WS2heterostructure is still a semiconductor with band gap of1.58eV, which is smaller than that of MoS2and WS2monolayer. However, the strong interactions between MoS2and MoTe2at the interfacial sites induce MoS2-MoTe2heterostructure showing metallic characters.(2) Then we studied the geometric structure, electronic structure and magnetic properties of Fe-doped MoS2monolayer by analyzing the variation of the total density of states (TDOS) and the distribution of spin density. When we increased the doping concentration, the Fe-doped systems would turn from semiconductor to half-metal or metal and the structure can not keep the hexagon. In addition, the total magnetic moment is2μB for the lower doping concentration and the total magnetic moment of the Fe-doped systems did not vary monotonically for the higher doping concentration. The total magnetic moment is almost0μB when the the doping concentration is between15%and25%. To calculate the energy difference between the Antiferromagnetic (AFM) state and Ferromagnetic (FM) state, it turns out to be FM state because of the lower energy.In conclusion, we may apply the MoS2-WS2and MoS2-MoTe2heterostructure to adjust the band gap of the mixed system base on different aims and be the contacts of the MoS2-based nanoelectronic devices. The Fe-doped MoS2monolayer can have a magnetic moment. To modify the properties of MoS2monolayer will extend the application of MoS2monolayer in the many fields. This theoretical study may stimulate further experimental studies of the low-dimensional heterostructues and become an important complement to the existing theoretical and experimental results.