DC Spin Current Generation in a Rashba-type Quantum Channel

TL;DR

This paper demonstrates theoretically that resonant inelastic scattering in a Rashba quantum channel enables dc spin current generation using a simple gate setup, with potential for enhanced spin currents in double-gate configurations.

Contribution

It introduces a novel mechanism for dc spin current generation via RIS in a Rashba channel with a single or double finger-gate, without producing charge current.

Findings

DC spin current can be generated via RIS with a single finger-gate.

The spin current depends on static and dynamic Rashba parameters, proportional to α₀α₁².

Double finger-gate configuration significantly enhances spin current.

Abstract

We propose and demonstrate theoretically that resonant inelastic scattering (RIS) can play an important role in dc spin current generation. The RIS makes it possible to generate dc spin current via a simple gate configuration: a single finger-gate that locates atop and orients transversely to a quantum channel in the presence of Rashba spin-orbit interaction. The ac biased finger-gate gives rise to a time-variation in the Rashba coupling parameter, which causes spin-resolved RIS, and subsequently contributes to the dc spin current. The spin current depends on both the static and the dynamic parts in the Rashba coupling parameter, $\alpha_0$ and $\alpha_1$, respectively, and is proportional to $\alpha_0 \alpha_1^2$. The proposed gate configuration has the added advantage that no dc charge current is generated. Our study also shows that the spin current generation can be enhanced significantly in a double finger-gate configuration.