Mesoscopic Aharonov-Bohm oscillations in metallic rings

TL;DR

This paper investigates mesoscopic Aharonov-Bohm oscillations in metallic rings, analyzing how coherence and dephasing affect oscillation amplitude at various temperatures, revealing a ring-dependent dephasing length distinct from standard values.

Contribution

It introduces a detailed analysis of the dephasing length specific to Aharonov-Bohm oscillations, showing its dependence on ring circumference and temperature regimes.

Findings

Dephasing length L_phi^AB is different from the standard dephasing length in Q1D systems.

Oscillation amplitude is suppressed at higher temperatures due to electron-electron interactions.

The variance of oscillation harmonics depends on lead length and temperature regime.

Abstract

We study the amplitude of mesoscopic Aharonov-Bohm oscillations in quasi-one-dimensional (Q1D) diffusive rings. We consider first the low-temperature limit of a fully coherent sample. The variance of oscillation harmonics is calculated as a function of the length of the leads attaching the ring to reservoirs. We further analyze the regime of relatively high temperatures, when the dephasing due to electron-electron interaction suppresses substantially the oscillations. We show that the dephasing length L_phi^AB governing the damping factor exp(-2pi R /L_phi^AB) of the oscillations is parametrically different from the common dephasing length for the Q1D geometry. This is due to the fact that the dephasing is governed by energy transfers determined by the ring circumference 2pi R, making L_phi^AB R-dependent.