Seminário do Departamento de Física dos Materiais e Mecânica
Spin-Orbit Interaction and Related Transport Phenomena in 2D Electron and Hole Systems
Dr. Alexander Khaetskii
Department of Physics, University at Buffalo, SUNY, Buffalo, NY
Data: 27 de julho de 2015 (segunda-feira)
Horário: às 14h
Local: Sala de Seminários José Roberto Leite - Ed. Alessandro Volta (bloco C) - andar térreo
Abstract
Spin-orbit interaction is responsible for many physical phenomena which are under intensive study currently. Here we discuss several of them.
The first phenomenon is the edge spin accumulation, which appears due to spin-orbit interaction in 2D mesoscopic structures in the presence of a charge current. We consider the case of a strong spin-orbit-related splitting of the electron spectrum, i.e. a spin precession length is small compared to the mean free path l. The structure can be either in a ballistic regime (when the mean free path is the largest scale in the problem) or quasi-ballistic regime (when l is much smaller than the sample size).
We show how physics of edge spin accumulation in different situations should be understood from the point of view of unitarity of boundary scattering. Using transparent method of scattering states, we are able to explain some previous puzzling theoretical results. In particular, we clarify the important role of the form of the spin-orbit Hamiltonian, the role of the boundary conditions, etc. The relation between the edge spin density and the bulk spin current in different regimes is discussed.
Besides, we consider several new transport phenomena which appear in the presence of spin-orbit interaction, for example, magnetotransport phenomena in an external classical magnetic field. In particular, new mechanism of negative Magnetoresistance appears which is due to destruction of spin fluxes by the magnetic field, and which can be really pronounced in 2D systems with strong scatterers.
