Electron-Dephasing Time in A Two-Dimensional Spin-Polarized System with Rashba Spin-Orbit Interaction

TL;DR

This paper calculates the electron dephasing time in a two-dimensional spin-polarized system with Rashba spin-orbit interaction, revealing a universal dependence on magnetic field and confirming experimental observations.

Contribution

It provides a theoretical analysis of how dephasing time varies with magnetic field in spin-polarized systems with Rashba interaction, extending understanding of spin-related quantum coherence.

Findings

Dephasing rate depends on the ratio of Zeeman energy to spin-orbit interaction.

Dephasing rate saturates at high magnetic fields, approaching twice the spin relaxation rate.

Results confirm experimental observations of dephasing behavior in such systems.

Abstract

We calculate the dephasing time $\tau_{\phi}(B)$ of an electron in a two-dimensional quantum well with a Rashba spin-orbit interaction, spin-polarized by an arbitrarily large magnetic field parallel to the layer. $\tau_\phi (B)$ is estimated from the logarithmic corrections to the conductivity, within a perturbative approach, that assumes weak isotropic disorder scattering. Our result indicates that for any value of the magnetic field, the dephasing rate changes with respect to its unpolarized state value by a universal function whose parameter is the ratio of the Zeeman splitting energy $(E_Z)$ to the spin-orbit interaction $(E_{SOI})$, confirming the experimental report published in Phys. Rev. Lett. {\bf 94}, 186805 (2005) . In the high field limit, when $E_Z>>E_{SOI}$, the dephasing rate saturates and reaches asymptotically to a value equal to twice the spin relaxation rate.