SPONTANEOUS SPIN POLARIZATION OF ELECTRONS IN SiGe/Si HETEROSTRUCTURES

2010 ◽  
Vol 09 (05) ◽  
pp. 503-509
Author(s):  
A. JOHN PETER
Keyword(s):  
Zero Magnetic Field ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Resonant Level ◽  
Electron Transmission ◽  
Rashba Spin ◽  
Spin Polarized ◽  
Spin Filters ◽  
Spin Injectors ◽  
The One

The spin-dependent electron transmission phenomenon in an SiGe/Si/SiGe resonant semiconductor heterostructure is employed theoretically to investigate the output transmission current polarization at zero magnetic field. Transparency of electron transmission is calculated as a function of electron energy as well as the well width, within the one electron band approximation along with the spin-orbit interaction. Enhanced spin-polarized resonant tunneling in the heterostructure due to Dresselhaus and Rashba spin-orbit coupling induced splitting of the resonant level is observed. We predict that a spin-polarized current spontaneously emerges in this heterostructure and we estimate theoretically that the polarization can reach 100%. This effect could be employed in the fabrication of spin filters, spin injectors, and detectors based on nonmagnetic semiconductors.

Rashba spin-orbit coupling in InGaAs/InP quantum wires

2004 ◽  
Vol 825 ◽  
Author(s):  
Jens Knobbe ◽  
Vitaliy A. Guzenko ◽  
Thomas Schäpers
Keyword(s):  
Quantum Wires ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
One Dimensional ◽  
Rashba Spin ◽  
Wet Chemical ◽  
Wet Chemical Etching ◽  
The One ◽  
Rashba Coupling

AbstractThe effect of Rashba spin-orbit coupling on the transport properties of InGaAs/InP quantum wire structures is investigated. The geometry of the wire structures was defined by selective wet chemical etching. For wires without a gate a clear beating pattern, due to the presence of the Rashba spin-orbit coupling, is observed for wires with a width down to 600 nm. For narrower wires no beating pattern is found. The experimental observations are explained by contribution of the Rashba spin-orbit coupling to the one-dimensional magnetosubbands. By depleting the one-dimensional conductor by means of a gate electrode the Rashba coupling strength could be controlled.

scholarly journals Manipulation of Majorana bound states in proximity to a quantum ring with Rashba coupling

2021 ◽  
Author(s):  
Fabían Gonzalo Medina ◽  
Dunkan Martínez ◽  
Alvaro Díaz-Fernández ◽  
Francisco Domínguez-Adame ◽  
Luis Rosales ◽  
...  
Keyword(s):  
Bound States ◽  
Orbit Coupling ◽  
Quantum Ring ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Persistent Currents ◽  
Zero Modes ◽  
Rashba Spin ◽  
Spin Polarized ◽  
Rashba Coupling

Abstract The quest for Majorana zero modes in the laboratory is an active field of research in condensed matter physics. In this regard, there have been many theoretical proposals; however, their experimental detection remains elusive. In this article, we present a realistic setting by considering a quantum ring with Rashba spin-orbit coupling and threaded by a magnetic flux, in contact with a topological superconducting nanowire. We focus on spin-polarized persistent currents to assess the existence of Majorana zero modes. We find that the Rashba spin-orbit coupling allows for tuning the position of the zero modes and has sizable effects on spin-polarized persistent currents. Our results pave the way towards probing the existence of Majorana zero modes.

scholarly journals Spin-Polarized Electron Transmission in DNA-Like Systems

Biomolecules ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 49 ◽  
Author(s):  
Miguel A. Sierra ◽  
David Sánchez ◽  
Rafael Gutierrez ◽  
Gianaurelio Cuniberti ◽  
Francisco Domínguez-Adame ◽  
...  
Keyword(s):  
Orbit Coupling ◽  
Theoretical Modelling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Chiral Molecules ◽  
Electronic Density ◽  
Coupling Interaction ◽  
Molecular Systems ◽  
Electron Transmission ◽  
Spin Polarized

The helical distribution of the electronic density in chiral molecules, such as DNA and bacteriorhodopsin, has been suggested to induce a spin–orbit coupling interaction that may lead to the so-called chirality-induced spin selectivity (CISS) effect. Key ingredients for the theoretical modelling are, in this context, the helically shaped potential of the molecule and, concomitantly, a Rashba-like spin–orbit coupling due to the appearance of a magnetic field in the electron reference frame. Symmetries of these models clearly play a crucial role in explaining the observed effect, but a thorough analysis has been largely ignored in the literature. In this work, we present a study of these symmetries and how they can be exploited to enhance chiral-induced spin selectivity in helical molecular systems.

The enhancement of electron transportation and photo-catalytic activity for hydrogen generation by introducing spin-polarized current into dye-sensitized photo-catalyst

2016 ◽  
Vol 6 (21) ◽  
pp. 7693-7697 ◽  
Author(s):  
Wenyan Zhang ◽  
Gongxuan Lu
Keyword(s):  
Catalytic Activity ◽  
Hydrogen Generation ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Photo Catalyst ◽  
Photo Catalytic Activity ◽  
Dye Sensitized ◽  
Rashba Spin ◽  
Spin Polarized ◽  
Electron Transportation

Implanting polyiodides into graphene not only realized spin-polarization of photo electrons, but induced an optimum Rashba spin–orbit coupling to promote the spin electrons tunneling through the honeycomb sub-lattices of graphene, thus the HER and TOF was highly improved.

Spin-polarized electron transmission resonance through a driven quantum well with spin-orbit coupling

2014 ◽  
Vol 28 (26) ◽  
pp. 1450203
Author(s):  
Xiu-Huan Ding ◽  
Cun-Xi Zhang ◽  
Rui Wang
Keyword(s):  
Quantum Well ◽  
Incident Electron ◽  
Orbit Coupling ◽  
Pure Spin ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Transmission Resonance ◽  
Electron Transmission ◽  
Spin Filters ◽  
Type Oscillation

In this paper, we study the spin-dependent electron transmission through a quantum well in semiconductor heterostructures with dipole-type oscillation field and homogeneous oscillation field. The numerical evaluations show that Dresselhaus spin-orbit coupling eliminates the spin degeneracy and leads to the splitting of asymmetric Fano-type resonance peaks in the transmissivity. The width of the splitting peaks is found to be highly sensitive to the direction of incident electron. The dipole modulation and the homogeneous modulation is approximately equivalent under certain conditions. The location and the line shape of the Fano-type resonance can be controlled by adjusting the energy and the direction of the incident electron, the oscillation frequency, and the amplitude of the external field. These interesting features may be used to devise tunable spin filters and realize pure spin transmission currents by the more practical dipole-type oscillation in the experimental setup.

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