Dynamic Magneto-Conductance Fluctuations and Oscillations in Mesoscopic Wires and Rings

TL;DR

This paper investigates the frequency-dependent behavior of magneto-conductance fluctuations and oscillations in disordered mesoscopic wires and rings using a recursive Green's function approach, revealing ergodic behavior and suppression effects at high frequencies.

Contribution

It introduces a self-consistent method to analyze dynamic conductance fluctuations and oscillations, highlighting frequency-dependent suppression phenomena in mesoscopic systems.

Findings

Real part of conductance fluctuations aligns with dc universal conductance fluctuations at low frequencies.

Imaginary part of conductance fluctuations increases linearly with frequency at low frequencies.

High-frequency suppression of Al'tshuler-Aronov-Spivak oscillations observed.

Abstract

Using a finite-frequency recursive Green's function technique, we calculate the dynamic magneto-conductance fluctuations and oscillations in disordered mesoscopic normal metal systems, incorporating inter-particle Coulomb interactions within a self-consistent potential method. In a disordered metal wire, we observe ergodic behavior in the dynamic conductance fluctuations. At low $\omega$, the real part of the conductance fluctuations is essentially given by the dc universal conductance fluctuations while the imaginary part increases linearly from zero, but for $\omega$ greater than the Thouless energy and temperature, the fluctuations decrease as $\omega^{-1/2}$. Similar frequency-dependent behavior is found for the Aharonov-Bohm oscillations in a metal ring. However, the Al'tshuler-Aronov-Spivak oscillations, which predominate at high temperatures or in rings with many channels, are strongly suppressed at high frequencies, leading to interesting crossover effects in the $\omega$-dependence of the magneto-conductance oscillations.