Electronic And Magnetic Properties Of SnSe Monolayer Doped:A First-principles Study

Along with the discovery of graphene in the experiment, many new two-dimensional(2D) atomic layered systems(such as, silicene, germanene, stanene,and phospherene and so on)have attracted special attention for future electronic application. Grapheme has presented ultrathin, excellent conductive and thermal conductivity, high electron mobility and quantum hall effect and so on. In addition,2D materials have many special electronic, optical, and mechanical properties due to their unique dimension-dependent properties compared with 3D materials. Recently,more and more researchers devoted themselves to 2D materials of graphene-analogous structure. Similar to the scope of group IV semiconductor,grapheme, silicene, and germanene have been broadened significantly by introducing isoelectronic III-V compounds, and phosphorene, arsenene, and antimonene have been broadened by introducing isoelectronic IV-VI compounds, this method has been applied to many fields. IV-VI group semiconductors have layered structures which are similar to phosphorene.SnSe monolayer with an orthorhombic Pnma Ge S structure, namely distortion Na Cl structure, is an important two-dimensional(2D) indirect band gap material at room temperature. Based on first-principles density functional theory calculations(DFT), we present systematic studies of the electronic and magnetic properties, which is SnSe monolayer in theory. And then, the basic electronic and magnetic properties of doping systems by III group atoms(Ga, In, and Tl)and V group atoms(As, Sb, and Bi) to substituted doped Sn in SnSe monolayer, and by V group atoms(As and Sb) and VII atoms(Br and I) to substituted doped Se atom in monolayer. We describe clear pictures and correlation analysis. Moreover, the formation energy of doping systems have been calculated. So that SnSe monolayer has the important practical value.The first chapter, in this chapter, we introduce the bulk and monolayer IV-VI simply, and mainly focus on the bulk and monolayer SnSe.The second chapter, the first-principle theory is been describe simply, this chapter mainly expound the main concepts and theorem of DFT. Moreover, we makethe simple introduce of the software package VASP, the calculation model, and parameters, which are used in our calculation.The third chapter, the electronic and magnetic properties of SnSe bulk and Sn monolayer are studied, and then we compare the properties.The fourth chapter, base on the SnSe monolayer, Sn atom is substituted doping by the third group atoms(Ga, In and Tl) and the fifth group atoms(As, Sb and Bi),respectively. And then, we studied the electronic and magnetic properties of six substitutional doping systems. Finally, we compare the results by same group atoms doped, and make the corresponding interpretation.The fifth chapter, in SnSe monolayer, the Se atom is replaced by the fifth group atoms(As and Sb) and the seventh group atoms(Br and I), respectively. The electronic and magnetic properties of doping systems are researched, and give a explanation.The sixth chapter, the full text summary. In this chapter, we analyze the electronic and magnetic properties of substitutional doping systems. In the doping systems, Sn atom and Se atom is substituted doping by different atoms in SnSe monolayer.