Thermal Spin Transport Properties Of Low Dimensional Nanometer Materials And Numerical Simulation Of Linear Perturbation Of High Dimensional Charged Black Holes

It can be said that numerical simulation plays an important role in the study of material properties and black hole physics.At present,the common numerical calculation methods include discretization of differential equations,processing of boundary conditions,etc.Density functional theory(DFT)and first-principles methods are often used in the field of computational materials.In addition,WKB approximation,finite difference method and continuous fraction method are widely used in the study of black hole physics.After the calculation method and coordinate system are determined,we can carry out calculation and analysis by compiling corresponding programs or using software packages.In the research of modern mathematical physics,this part of work is the main body of the whole research work.Through numerical simulation calculation,a large number of data can be vividly displayed through images,which makes the research of some new materials or physical problems more intuitive,but also saves a lot of experimental costs.Based on numerical simulation,especially the application of Schrodinger equation in density functional theory and WKB approximation method,two aspects are studied in this paper.In the first part,thermal spin transport properties of some low-dimensional nanomaterials are studied based on density functional theory and non-equilibrium Green’s function method.In the second part,the linear perturbation of a high-dimensional charged black hole in a scalar field is studied by using the sixth order WKB approximation.The thermal spin transport properties of some nanomaterials and devices are simulated and calculated using the ATK software package in part one.This part is composed of three chapters.The first chapter is the introduction,which mainly introduces the density functional theory non-equilibrium state Green’s function method and the Seebeck effect.In chapter 2,the thermal spin transport properties of nitrobenzene diazo functionalized graphene nanosheets and their thermoelectric optimal values are studied,which provides theoretical guidance for their applications in thermal spintronics devices.In the third chapter,the electronic structure of the device composed of covalent functionalized carbon nanotubes(CNTs)of BN nanoribbon is studied,and the ferromagnetism and conductivity of different configurations are compared and analyzed.Then,a novel thermal spintronics device was designed based on the serrated BN nanoribbon covalent functionalized carbon nanotubes,and the thermal spin filtering effect and spin-dependent Seebeck effect of the device based on ZBNRS-N-(6,6)SWCNT were investigated.The second part is divided into two chapters.The first chapter briefly introduces the black hole and its quasi positive size,introduces the main calculation method(WKB approximation)used in this part,and explains the research status and significance of the quasi positive size of black hole.In the second chapter,the perturbations of a high-dimensional Reissner Nordstrom-de Ssitter(RN-d S)black hole in a massless scalar field are numerically calculated and discussed by using the WKB approximation method.In this chapter,we first introduce the RN-DS black holes and their perturbations,and study the relationship between the quasi-scale frequency and the angular quantum number cosmological constant and the quantity of charge.Then we discuss the effect of dimension and charge on the radius of black hole shadow,and discuss the quasi positive size of RN-DS black hole in different dimensions.Finally,the absorption cross sections of RN-d S black holes with different dimensions are given.