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The limit spin current in a time-dependent Rashba spin-orbit coupling system.

Shu-feng Zhang¹, Wei Zhu

¹Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.

Journal of Physics. Condensed Matter : an Institute of Physics Journal

|January 19, 2013

Summary

This study explores generating spin current in electron gas systems using time-varying Rashba spin-orbit coupling (RSOC). Pulsed spin currents can reach maximum achievable limits, with findings extended to 2D systems and quantum dots.

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Area of Science:

Condensed matter physics
Spintronics
Quantum mechanics

Background:

Spin current generation is crucial for spintronics.
Rashba spin-orbit coupling (RSOC) offers a tunable mechanism for spin manipulation.
Understanding spin dynamics in low-dimensional systems is key.

Purpose of the Study:

To investigate spin current generation in a 1D electron gas (1DEG) with time-varying RSOC.
To analyze the impact of modulated gate voltage on spin-dependent potentials and fields.
To extend the findings to 2D systems and metal-quantum dot-metal structures.

Main Methods:

Unitary transformation to derive spin-dependent potentials and effective fields.
Relaxation approximation to incorporate scattering interactions.
Derivation of the induced spin current formula and estimation of its magnitude.

Main Results:

A time-varying gate voltage modulates RSOC, inducing a spin-dependent potential and effective electric field.
The derived formula allows calculation of induced spin current.
Maximum pulsed spin current can reach a specific limit value, estimated in order of magnitude.
Results are applicable to both 1DEG and 2DEG systems, and metal-quantum dot-metal systems.

Conclusions:

Time-varying RSOC is an effective method for generating significant spin currents.
The theoretical framework provides a basis for designing spintronic devices.
The study offers insights into spin transport in various quantum systems.