Quantum transport in a curved one-dimensional quantum wire with spin-orbit interactions

TL;DR

This paper develops an effective Hamiltonian for a curved 1D quantum wire with spin-orbit interaction, analyzing electron transport, reflection, transmission, and spin polarization effects influenced by device geometry and spin-orbit strength.

Contribution

It introduces a new effective Hamiltonian for curved quantum wires with spin-orbit coupling and analytically studies electron transport and spin polarization in such geometries.

Findings

Reflection probabilities depend mainly on arc angle and radius.

Transmission probabilities are affected by spin-orbit coupling and geometry.

Conductance oscillates with device parameters and electron energy.

Abstract

The one-dimensional effective Hamiltonian for a planar curvilinear quantum wire with arbitrary shape is proposed in the presence of the Rashba spin-orbit interaction. Single electron propagation through a device of two straight lines conjugated with an arc has been investigated and the analytic expressions of the reflection and transmission probabilities have been derived. The effects of the device geometry and the spin-orbit coupling strength $\alpha$ on the reflection and transmission probabilities and the conductance are investigated in the case of spin polarized electron incidence. We find that no spin-flip exists in the reflection of the first junction. The reflection probabilities are mainly influenced by the arc angle and the radius, while the transmission probabilities are affected by both spin-orbit coupling and the device geometry. The probabilities and the conductance take the general behavior of oscillation versus the device geometry parameters and $\alpha $. Especially the electron transportation varies periodically versus the arc angle $\theta_{w}$. We also investigate the relationship between the conductance and the electron energy, and find that electron resonant transmission occurs for certain energy. Finally, the electron transmission for the incoming electron with arbitrary state is considered. For the outgoing electron, the polarization ratio is obtained and the effects of the incoming electron state are discussed. We find that the outgoing electron state can be spin polarization and reveal the polarized conditions.