Spin-Orbit Interaction and Related Transport Phenomena in 2D Electron and Hole Systems

Data: 
27/07/2015 - 14:00 até 15:00
Palestrante: 
Dr. Alexander Khaetskii
Local: 
Sala de Seminários José Roberto Leite - Ed. Alessandro Volta (bloco C) - térreo
Resumo: 
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.