Electronic dephasing in wires due to metallic gates

TL;DR

This paper investigates how metallic gates cause electron dephasing in quasi-one-dimensional diffusive wires, modeling the effect as fluctuating electric fields and estimating the temperature dependence of the dephasing time.

Contribution

It introduces a model describing gate-induced dephasing as an environment coupling, providing a simple estimate of the inverse dephasing time proportional to the square root of temperature.

Findings

Dephasing time inverse scales as T^{1/2} at high energies or temperatures.

The system can be modeled as a Caldeira-Leggett environment coupled to electrons.

Incomplete screening leads to electric field fluctuations affecting electron coherence.

Abstract

The dephasing effect of metallic gates on electrons moving in one quasi--one--dimensional diffusive wires is analyzed. The incomplete screening in this geometry implies that the effect of the gate can be described, at high energies or temperatures, as an electric field fluctuating in time. The resulting system can be considered a realization of the Caldeira-Leggett model of an environment coupled to many particles. Within the range of temperatures where this approximation is valid, a simple estimation of the inverse dephasing time gives $\tau_{\rm G}^{-1} \propto T^{1/2}$.