scholarly journals Spin Relaxation in Germanium Nanowires

2012 ◽  
Vol 2012 ◽  
pp. 1-7
Author(s):  
Ashish Kumar ◽  
M. W. Akram ◽  
Bahniman Ghosh
Keyword(s):  
Electric Field ◽  
Spin Relaxation ◽  
Spin Density Matrix ◽  
Relaxation Length ◽  
Germanium Nanowires ◽  
Spin Dephasing ◽  
Electric Field Dependence ◽  
Spin Polarized ◽  
Structural Inversion ◽  
Inversion Asymmetry

We use semiclassical Monte Carlo approach along with spin density matrix calculations to model spin polarized electron transport. The model is applied to germanium nanowires and germanium two-dimensional channels to study and compare spin relaxation between them. Spin dephasing in germanium occurs because of Rashba Spin Orbit Interaction (structural inversion asymmetry) which gives rise to the D’yakonov-Perel (DP) relaxation. In germanium spin flip scattering due to the Elliot-Yafet (EY) mechanism also leads to spin relaxation. The spin relaxation tests for both 1D and 2D channels are carried out at different values of temperature and driving electric field, and the variation in spin relaxation length is recorded. Spin relaxation length in a nanowire is found to be much higher than that in a 2D channel due to suppression of DP relaxation in a nanowire. At lower temperatures the spin relaxation length increases. This suggests that spin relaxation in germanium occurs slowly in a 1D channel (nanowires) and at lower temperatures. The electric field dependence of spin relaxation length was found to be very weak.

scholarly journals MONTE CARLO SIMULATION OF SPIN RELAXATION IN NANOWIRES AND 2-D CHANNELS OF II–VI SEMICONDUCTORS

SPIN ◽  
2012 ◽  
Vol 02 (02) ◽  
pp. 1250007 ◽  
Author(s):  
ASHUTOSH SHARMA ◽  
SWETALI NIMJE ◽  
AKSHAYKUMAR SALIMATH ◽  
BAHNIMAN GHOSH
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
External Field ◽  
Spin Relaxation ◽  
Simulation Method ◽  
Relaxation Length ◽  
Factors Affecting ◽  
Spin Dephasing ◽  
Spin Polarized ◽  
The Many

We have analyzed spin relaxation behavior of various II–VI semiconductors for nanowire structure and 2-D channel by simulating spin polarized transport through a semiclassical approach. Monte Carlo simulation method has been applied to simulate our model. D'yakonov–Perel mechanism and Elliot–Yafet mechanism are dominant for spin relaxation in II–VI semiconductors. Variation in spin relaxation length with external field has been analyzed and comparison is drawn between nanowire and 2-D channels. Spin relaxation lengths of various II–VI semiconductors are compared at an external field of 1 kV/cm to understand the predominant factors affecting spin dephasing in them. Among the many results obtained, most noticeable one is that spin relaxation length in nanowires is many times greater than that in 2-D channel.

RESONANT SPIN POLARIZATION IN A TWO-DIMENSIONAL HOLE GAS

2011 ◽  
Vol 25 (15) ◽  
pp. 1259-1270
Author(s):  
TIANXING MA
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Spin Polarization ◽  
Zeeman Splitting ◽  
Resonant Peak ◽  
Two Dimensional ◽  
Structural Inversion ◽  
Inversion Asymmetry ◽  
Peak Increase ◽  
Luttinger Hamiltonian

Within the Luttinger Hamiltonian, electric-field-induced resonant spin polarization of a two-dimensional hole gas in a perpendicular magnetic field was studied. The spin polarization arising from splitting between the light and the heavy hole bands shows a resonant peak at a certain magnetic field. Especially, the competition between the Luttinger term and the structural inversion asymmetry leads to a rich resonant peaks structure, and the required magnetic field for the resonance may be effectively reduced by enlarging the effective width of the quantum well. Furthermore, the Zeeman splitting tends to move the resonant spin polarization to a relative high magnetic field and destroy these rich resonant spin phenomena. Finally, both the height and the weight of the resonant peak increase as the temperature decreases. It is believed that such resonant spin phenomena may be verified in the sample of a two-dimensional hole gas, and it may provide an efficient way to control spin polarization by an external electric field.

EFFECT OF ELECTRIC FIELD, TEMPERATURE AND CORE DIMENSIONS IN III–V COMPOUND CORE–SHELL NANOWIRES

NANO ◽  
2014 ◽  
Vol 09 (04) ◽  
pp. 1450051
Author(s):  
ASHWANI VERMA ◽  
BAHNIMAN GHOSH ◽  
AKSHAY KUMAR SALIMATH
Keyword(s):  
Monte Carlo ◽  
Electric Field ◽  
Spin Relaxation ◽  
Compound Semiconductor ◽  
Core Shell ◽  
Relaxation Length ◽  
The Core ◽  
Field Temperature ◽  
Simulation Results ◽  
Shell Nanowires

In this paper, we have used semiclassical Monte Carlo method to show the dependence of spin relaxation length in III–V compound semiconductor core–shell nanowires on different parameters such as lateral electric field, temperature and core dimensions. We have reported the simulation results for electric field in the range of 0.5–10 kV/cm, temperature in the range of 77–300 K and core length ranging from 2 nm to 8 nm. The spin relaxation mechanisms used in III–V compound semiconductor core–shell nanowire are D'yakonov–Perel (DP) relaxation and Elliott–Yafet (EY) relaxation. Depending upon the choice of materials for core and shell, nanowire forms two types of band structures. We have used InSb – GaSb core–shell nanowire and InSb – GaAs core–shell nanowire and nanowire formed by swapping the core and shell materials to show all the results.

scholarly journals Temperature and Electric Field Dependence of Spin Relaxation in Graphene on SrTiO3

2018 ◽  
Vol 12 (11) ◽  
pp. 1800216 ◽  
Author(s):  
Si Chen ◽  
Roald Ruiter ◽  
Vikramaditya Mathkar ◽  
Bart J. van Wees ◽  
Tamalika Banerjee
Keyword(s):  
Electric Field ◽  
Field Dependence ◽  
Spin Relaxation ◽  
Electric Field Dependence

scholarly journals Electric field dependence of the spin relaxation anisotropy in (111) GaAs/AlGaAs quantum wells

2013 ◽  
Vol 15 (9) ◽  
pp. 095016 ◽  
Author(s):  
A Balocchi ◽  
T Amand ◽  
G Wang ◽  
B L Liu ◽  
P Renucci ◽  
...  
Keyword(s):  
Electric Field ◽  
Quantum Wells ◽  
Field Dependence ◽  
Spin Relaxation ◽  
Electric Field Dependence

Electric field dependence of exciton spin relaxation in GaAs/AlGaAs quantum wells

1993 ◽  
Vol 63 (23) ◽  
pp. 3164-3166 ◽  
Author(s):  
A. Vinattieri ◽  
Jagdeep Shah ◽  
T. C. Damen ◽  
K. W. Goossen ◽  
L. N. Pfeiffer ◽  
...  
Keyword(s):  
Electric Field ◽  
Quantum Wells ◽  
Field Dependence ◽  
Spin Relaxation ◽  
Electric Field Dependence

Theory of Electrically Controlled Resonant Tunneling Spin Devices

2004 ◽  
Vol 825 ◽  
Author(s):  
David Z.-Y. Ting ◽  
Xavier Cartoixà
Keyword(s):  
Resonant Tunneling ◽  
High Speed ◽  
Current Source ◽  
Spin Orbit ◽  
Speed Modulation ◽  
Spin Polarized ◽  
Structural Inversion ◽  
Inversion Asymmetry ◽  
Spin Devices ◽  
High Speed Modulation

AbstractWe report device concepts that exploit spin-orbit coupling for creating spin polarized current sources using nonmagnetic semiconductor resonant tunneling heterostructures, without external magnetic fields. The resonant interband tunneling spin filter exploits large valence band spin-orbit interaction to provide strong spin selectivity. The bi-directional spin pump induces the simultaneous flow of oppositely spin-polarized current components in opposite directions through spin-dependent resonant tunneling. The efficiency of resonant tunneling spin devices can be improved when the effects of structural inversion asymmetry (SIA) and bulk inversion asymmetry (BIA) are combined properly, and incorporated into device design. The current spin polarizations of the proposed devices are electrically controllable, and potentially amenable to high-speed modulation. In principle, the electrically modulated spin-polarized current source could be integrated in optoelectronic devices for added functionality.

SPIN RELAXATION IN InP AND STRAINED InP NANOWIRES

SPIN ◽  
2014 ◽  
Vol 04 (03) ◽  
pp. 1450003
Author(s):  
AKSHAYKUMAR SALIMATH ◽  
BAHNIMAN GHOSH
Keyword(s):  
Cross Section ◽  
Spin Relaxation ◽  
Gaas Substrate ◽  
Relaxation Length ◽  
Transport Direction ◽  
Spin Polarized ◽  
Higher Spin ◽  
Wire Cross Section ◽  
Polarized Transport ◽  
Spin Polarized Transport

In this paper, we employ semiclassical Monte Carlo approach to study spin polarized transport in InP and strained InP nanowires on GaAs substrate. Due to higher spin relaxation lengths, InP is being researched as suitable III–V material for spintronics related applications. Spin relaxation in InP channel is as a result of D'yakonov–Perel (DP) relaxation and Elliott–Yafet (EY) relaxation. We have considered injection polarization along z-direction and the magnitude of ensemble averaged spin variation is studied along the x-direction i.e., along transport direction. The effect of strain on various scattering rates and spin relaxation length is studied. We then present the effect of variation of nanowire width on spin relaxation length for the case of both strained and unstrained InP nanowire. The wire cross-section is varied between 4 × 4 nm2 and 10 × 10 nm2.

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