Collective excitation of quantum wires and effect of spin-orbit coupling in the presence of a magnetic field along the wire

TL;DR

This paper theoretically investigates how collective excitations in quantum wires are affected by spin-orbit coupling and magnetic fields, revealing that the excitation velocity depends on these parameters, which could allow measurement of spin-orbit strength.

Contribution

It introduces a theoretical analysis of collective modes in quantum wires with Rashba spin-orbit coupling under magnetic fields, highlighting the dependence of excitation velocity on these factors.

Findings

Collective excitation velocity depends on Rashba spin-orbit strength and magnetic field.

Spin mixing at Fermi wavevectors is affected by the magnetic field.

Measurement of excitation velocity can determine spin-orbit interaction strength.

Abstract

The band structure of a quantum wire with the Rashba spin-orbit coupling develops a pseudogap in the presence of a magnetic field along the wire. In such a system spin mixing at the Fermi wavevectors $-k_F$ and $k_F$ can be different. We have investigated theoretically the collective mode of this system, and found that the velocity of this collective excitation depends sensitively on the strength of the Rashba spin-orbit interaction and magnetic field. Our result suggests that the strength of the spin-orbit interaction can be determined from the measurement of the velocity.