The Electronics Structure And Magnetic Properties Of2D Nano Material MoS₂Doped With Transition Metal Atoms

The two-dimensional semiconductor material MoS2has attracted a growingattention due to its special layered structure in recent years. In the existing studies, ithas indicated that MoS2can get an available magnetism with the substitutionaldoping of transition metal atoms, and is expected to be a new generation of dilutedmagnetic semiconductor (DMS). In general, people always care about the way whichcould obtain some magnetism, but neglect that MoS2might lose its ownsemiconductor characteristics at the same time, presenting a certain of semimetalproperties, as the result, it can’t be widely used as DMS. In addition, the properties ofmonolayer MoS2and bi-layer MoS2is not exactly the same because of its specialphysical and chemical characteristics. The research production of monolayer materialis not certain suitable for bi-layer material. Aiming at solving the above problems,theoretical study of electronic structure and magnetic properties has been made fordoping with transition metal atoms in this paper, according to monolayer MoS2andbi-layer MoS2respectively, and put forward the method of adjusting the semimetalproperties of doping systems, providing some semiconductor properties.In this paper, the plane wave pseudopotential method based on densityfunctional theory (DFT) were carried out, first, using the3×3×1supercell ofmonolayer MoS2as the calculation model for the first principle calculations, resultsshow that the pure MoS2does not have magnetism, and MoS2doped with Cr atomhas no significant magnetism, while V, Mn, Fe doped MoS2get an obviousmagnetism distinctly, in addition, MoS2doped with Mn and Fe atoms gain a largermagnetism, but show some semimetal properties as the doping system. For Mndoped MoS2, this paper proposes a method of doping with Si atom in VI family, theoutcome reflect that the semimetal characteristic of Mn-doped MoS2has been changed cause ofintroduction of Si atom, becomes an indirect bandgap semiconductor for the the conductionband minimum at G point while the the valence band maximum at K point, and thebandgap is0.7eV. Besides of this, the magnetic moment of co-doped MoS2is equal to Mn-doped MoS2mostly. For Fe doped MoS2, choosing N atom in V family as the step doping could adjustits semimetal characteristics, Fe, N co-doped MoS2has magnetism, is an indirect bandgapsemiconductor with0.2eV bandgap.Secondly, we use a3×3×1supercell of bi-layer MoS2as the model for firstprinciple calculations. The results show that un-doped bi-layer MoS2has nomagnetism, it is a semiconductor with direct bandgap, and the width of gap is1.590eV. Furthermore, the calculation results of doping with transition metal atomsshow that, besides Cr doped system having semimetal characteristics, other V, Mn,Fe respectively doped systems are all have semiconductor properties and magneticproperties also, they possess the desired conditions to become diluted magneticsemiconductor.