Physical Property Manipulation In Two-dimensional InSe Via Arsenic Doping

With the appearance of graphene and the size decrease of electronic devices,two–dimensional(2D)nanomaterials have attracted more and more attention and new materials continue emerging.Recently,from the three-dimensional layered bulk indium selenide(InSe),researchers in the University of Manchester and Nottingham have obtained two-dimensional single layer InSe in lab.The atomically thick InSe,which is known as the"golden point of graphene and silicon",should make the large family of 2D material more colorful due to its unique physical properties.In this thesis,employing the density functional theory based on the first principles,we have studied the manipulation of electronic and magnetic properties of single layer InSe via doping of arsenic atoms.The arsenic doping can introduce a single layer InSe,which is originally nonmagnetic semiconductor,a variety of physical properties such as magnetism,metallicity,half metallicity,and even half semimetallicity.We firstly summarize the development and potential applications of 2D materials.The geometry structure and basic properties of bulk and single layer InSe,as well as the preparation method and potential applications in electronic and optical devices of 2D single layer InSe.Then we introduce our simulation tools(ATK and VASP)and overview the density functional theory.On this basis we finally elaborate on our work during the master's study and give a summary.Using 3×3?2×2 and 4×4 supercell models,the intriguing structural?electronic and magnetic properties of a single InSe quadruple layer doped with arsenic atoms have been investigated by first-principles analysis.The simulation of density functional theory shows that an isolate As dopant in InSe quadruple layer is spin split by an energy of 0.17 eV in p_z orbital and has a magnetic moment of 0.352?_B.The coupling between two As atoms can change from antiferromagnetic to ferromagnetic with the increase of distance.A cluster of three nearest neighbor dopants shows half metal characters.Through systematic study,we can draw the following conclusions:(1)the layer can be manipulated by As dopants into nonmagnetic/magnetic semiconductor/metal and even half semimetal with a single spin cone energy band at the Fermi energy;(2)the quadruple laye becomes more conductive with the increase of doping density;(3)At low doping density with odd number of dopants per supercell,the layer is more likely to be magnetic.These properties endows InSe nanomaterials many potential applications in the novel integrated functional nanodevices.