First-principles Study On The Electromagnetic Characteristics Of MoX₂/BN?X=S,Se? Heterostructure

In recent years,the transition metal chalcogenides represented by molybdenum disulfide?MoS₂?have become new stars in the two-dimensional material field due to their tunable semiconductor electronic structure and a series of excellent electrical and optical properties.Hexagonal boron nitride?h-BN?crystals are often used as substrates and packaging materials because of their smooth and flat surfaces and unique properties.In particular,theVan der Waals heterostructure produced by the superposition of two single-layer semiconductors shows a variety of unique physical properties,and thus has been rapidly developed experimentally.Van der Waals heterostructures are physically assembled together by relatively weak Van der Waals interaction forces,do not rely on chemical bonds,and are not limited to the degree of lattice matching of materials,bringing new dawn to the electronics and optoelectronic device industry.All work in this paper is performed in a heterostructure composed of transition metal chalcogenide and Boron Nitride(MoS_xSe_2-x/h-BN).This work uses the first-principles calculation method based on density functional theory?DFT?,we mainly studied the situation of MoS_xSe_2-x-x on the h-BN substrate,and studied the geometric structure,electronic characteristics,and magnetic properties of MoS_xSe_2-x/h-BN heterostructure with different concentrations of Se atoms.By revealing the intrinsic mechanism of the h-BN substrate for MoS_x Se_2-x-x band gap regulation,we found that the substitution of Se atoms can significantly enhance the band gap of the MoS_xSe_2-x/h-BN heterostructure,and its band gap increases as the substitution concentration increases.When the substitution concentration exceeds a critical value,the energy band changes from an indirect band gap to a direct band gap.I believe that the results of our research will effectively improve the performance of the transition metal chalcogenide heterostructure and be better applied to the field of magnetic devices and optoelectronic devices.In addition,based on the previous work,the doping effect of TM doping in MoSe₂/h-BN heterostructure is studied.The results show that the structure of the doped TM heterojunction is still stable,and the doped TM atom can adjust the performance of MoSe₂/h-BN heterojunction.The results show that the doping of V,Mn,Fe and co atoms makes the heterojunction system show a semi metallic state and magnetic behavior,while in the case of Ni doping,there is no spin polarization,and the system does not show magnetism;and the TM atom can regulate MoSxSe_2-x/h-BN.The band structure,charge density and density of states of the heterojunction can also introduce magnetic moment into the system.The results will provide some theoretical guidance for the design of new nano spin devices,and provide a theoretical basis for the development of diluted magnetic semiconductors and spin devices based on MoS_xSe_2-x/h-BN heterostructures.