Spin currents in semiconductor nanostructures: A non-equilibrium Green-function approach

2017 ◽  
Author(s):  
Branislav K. Nikolic ◽  
Liviu P. Zarbo ◽  
Satofumi Souma
Keyword(s):  
Green Function ◽  
Spin Current ◽  
Semiconductor Nanostructures ◽  
Pure Spin ◽  
Current Operator ◽  
Spin Orbit ◽  
Spin Currents ◽  
Low Dimensional ◽  
Green Function Approach ◽  
Non Equilibrium

This article examines spin currents and spin densities in realistic open semiconductor nanostructures using different tools of quantum-transport theory based on the non-equilibrium Green function (NEGF) approach. It begins with an introduction to the essential theoretical formalism and practical computational techniques before explaining what pure spin current is and how pure spin currents can be generated and detected. It then considers the spin-Hall effect (SHE), and especially the mesoscopic SHE, along with spin-orbit couplings in low-dimensional semiconductors. It also describes spin-current operator, spindensity, and spin accumulation in the presence of intrinsic spin-orbit couplings, as well as the NEGF approach to spin transport in multiterminal spin-orbit-coupled nanostructures. The article concludes by reviewing formal developments with examples drawn from the field of the mesoscopic SHE in low-dimensional spin-orbit-coupled semiconductor nanostructures.

Spin Hall Effect Induced by Sound

2012 ◽  
Vol 190 ◽  
pp. 117-120
Author(s):  
I.I. Lyapilin
Keyword(s):  
Degrees Of Freedom ◽  
Spin Current ◽  
Coherent Motion ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Spin Coherence ◽  
Nanoscale Systems ◽  
The Subject ◽  
Normal Current ◽  
Low Dimensional

Transport of electronic spins in low-dimensional and nanoscale systems is the subject of thenovel and quickly developing eld of spintronics. The possibility of coherent spin manipulationrepresents an ultimate goal of this eld. Typically, spin transport is strongly aected by couplingof spin and orbital degrees of freedom. The inuence of the spin orbit interaction is twofold.The momentum relaxation due to the scattering of carriers, inevitably leads to spin relaxationand destroys the spin coherence. On the other hand, the controlled orbital motion of carrierscan result in a coherent motion of their spins. Thus, the spin orbit coupling is envisaged as apossible tool for spin controling in electronic devices. In particular, it is possible to generatespin polarization and spin currents by applying electric eld, the phenomenon known as thespin-Hall eect (SHE) [1- 3]. The eect is manifested in the form of a spin current directedperpendicular to the normal current, which takes place in an electric eld.

scholarly journals Production, detection, storage and release of spin currents

2015 ◽  
Vol 6 ◽  
pp. 736-743 ◽  
Author(s):  
Michele Cini
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Spin Current ◽  
Optical Excitation ◽  
Pure Spin ◽  
Field Methods ◽  
Magnetic Current ◽  
Spin Currents ◽  
New Phenomena ◽  
Storage Units

Background: Quantum rings connected to ballistic circuits couple strongly to external magnetic fields if the connection is not symmetric. Moreover, properly connected rings can be used to pump currents in the wires giving raise to a number of interesting new phenomena. At half filling using a time-dependent magnetic field in the plane of the ring one can pump a pure spin current, excited by the the spin–orbit interaction in the ring. Results: Such a magnetic current is even under time reversal and produces an electric field instead of the usual magnetic field. Numerical simulations show that one can use magnetizable bodies as storage units to concentrate and save the magnetization in much the same way as capacitors operating with charge currents store electric charge. The polarization obtained in this way can then be used on command to produce spin currents in a wire. These currents show interesting oscillations while the storage units exchange their polarizations. Conclusion: The magnetic production of spin currents can be a useful alternative to optical excitation and electric field methods.

scholarly journals Boundary conditions and Green function approach of the spin–orbit interaction in the graphitic nanocone

2017 ◽  
Vol 14 (09) ◽  
pp. 1750116 ◽  
Author(s):  
Jan Smotlacha ◽  
Richard Pincak
Keyword(s):  
Green Function ◽  
Analytical Form ◽  
Orbit Coupling ◽  
Boundary Effects ◽  
Function Approach ◽  
Electron Mass ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
The Green Function ◽  
Green Function Approach

The boundary effects affecting the Hamiltonian for the nanocone with curvature-induced spin–orbit coupling were considered and the corresponding electronic structure was calculated. These boundary effects include the spin–orbit coupling, the electron mass acquisition and the Coulomb interaction. Different numbers of the pentagonal defects in the tip were considered. The matrix and analytical form of the Green function approach was used for the verification of our results and the increase of their precision in the case of the spin–orbit coupling.

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