Spin-polarized dynamic transport in tubular two-dimensional electron gases

TL;DR

This paper investigates how Rashba spin-orbit interaction influences ac conductance, shot noise, and quantum capacitance in a tubular 2D electron gas, revealing spin-polarized currents and related phenomena.

Contribution

It provides a detailed analysis of spin-polarized transport and noise characteristics in tubular 2D electron gases with Rashba interaction, including new insights into quantum capacitance and charge relaxation.

Findings

Rashba interaction splits dc current steps, creating spin-polarized currents.

Shot noise reveals the presence of spin-polarized currents.

Quantum capacitance and charge-relaxation resistance show singularities at channel openings.

Abstract

The ac conductance of a finite tubular two-dimensional electron gas is studied in the presence of the Rashba spin-orbit interaction. When the tube is coupled to two reservoirs, that interaction splits the steps in the dc current, introducing energy ranges with spin-polarized currents. For this setup, we calculate the current-current correlations (the noise spectrum) and show that the existence of these dc spin-polarized currents can be deduced from the shot noise. We also find that the Wigner-Smith time delay is almost unaffected by the spin-orbit interaction. When the tube is coupled to a single reservoir, we calculate the quantum capacitance and the charge-relaxation resistance, and find that they exhibit singularities near the openings of new channels.