Spin Hall Effect And Spin Current In A Mesoscopic System With Spin-Orbit Coupling

Spintronics (or spin-electronics) is now a emerging research field of condensed matter physics, there are many basic physical problems in the task of spintronics, such as how to achieve spin injection, spin control and spin detection and so on. The spin transport based on the semiconductor heterostructures with spin-orbit coupling (SOC) and spin Hall effect as well as spin current has become a popular area of research in the growing field of spintronics recently, especially the ability to manipulate electron spin and spin current in mesoscopic system without external magnetic fields is of critical importance for the design of higher performance electronic components and storage devices. Therefore, it is of great significance to investigate the spin transport in mesoscopic systems with SOC.The thesis consists of five chapters. In chapter one, we give a briefly introduction to spin transport properties for the zinc-blende structure semiconductor heterostructures with SOC, including spin accumulation, spin precession, spin-polarized transport and spin current as well as spin Hall effect, etc. In chapter two, we introduce the concept of SOC in semiconductor heterostructures and describe the preparation and use of quantum well, quantum wire and quantum dot in band theory.In chapter three, we firstly give the background of spin Hall effect and its great significance in theory and application, and then discuss some characteristic of spin Hall conductance in a finite two dimensional electron gas system. After that, starting from the classic continuity equation, we construct a proper definition of spin current via analogy method and get the expression of spin current density in a SOC system.In chapter four, we design a infinite quantum wire system with Dresselhaus SOC, and investigate the persistent spin current in this system. By analyzing the results, we not only get a similar conclusion as that in previous works, and also find some new and interesting phenomenon. These results will play a key role in the detection and manipulate of spin currents, and have a good prospect of application.We give a briefly summary of our work and an outlook of this field in chapter five.