Influence Of Disorder And External Field On Electron Transport Properties In Two-dimensional Mesoscopic System

In order to discuss the transport phenomena,the first part of the article describes the research actuality and research methods of this problem.The electron transport in a two-dimensional system is studied by using Green function and scattering matrix theory.Base on the two-dimensional lattice model,the phenomenon of quantized conductance of the "sandwich" type electronic system is analyzed,also the electronic conductivity properties is analyzed by the Matlab.The first chapter mainly describes the research history of electron transport,and gives the achievements and current development direction of the electron transport process in micro system.The preliminary understanding of the electronic transport problem is shown.In the second chapter,the concept of mesoscopic system and the transport properties of electrons in mesoscopic system are introduced.After that,the transport process and theoretical analysis of the electron in the mesoscopic system are described.The third chapter introduces the method of Green's function theory of electron transport in mesoscopic system,.The general form of the Green function are described,then the recursive Green's function method for low dimensional system are introduced.Finally,the Green function of the system is obtained.Combining with the transmission coefficient of system,the conductance can be calculated.When the two-dimensional electron system is not affected by the external field,the fourth chapter gives the influence of the contact between the conducting wire and the scattering body.It showes that the contact and the disorder on the system reduces the system's conductance and whittle down the quantum conductance Stair-stepping phenomenon;When a external magnetic field acts on the system,the conductance presents a periodicity oscillation with the magnetic field.The intensity of this oscillation relates to the incident energy of the electron.In the fifth chapter,the same way is used to study the electron transport properties.The electronic conductivity is analyzed.When a electric field acts on two-dimensional system,because of the existence of quantum effect,the addition of electric field decreases the system conductance,and "step" quantum effect of system conductance is reduced,With the increase of the size of the intermediate scattering area,the oscillation of thesystem is increased.When the system is subjected to a external magnetic field,the system conductance decreases with the increase of the electric field,and varies with the magnetic field periodicly.The intensity of oscillation decreases with the increase of electric field;When it is dopped of the disorder,the scattering effect makes the conductance decrease with the increase of the disorder concentration.