1/f noise and slow relaxations in glasses

TL;DR

This paper links the spectrum of relaxation rates in electron glasses to the emergence of 1/f noise, providing a theoretical framework supported by numerical validation and discussing implications for local capacitance measurements.

Contribution

It introduces a theoretical relation between relaxation rate spectra and 1/f noise in electron glasses, extending understanding of slow relaxations and fluctuations in disordered systems.

Findings

The relaxation rate spectrum follows a 1/λ distribution.

The 1/λ spectrum leads to observable 1/f noise.

Numerical results confirm the analytical predictions.

Abstract

Recently we have shown that slow relaxations in the electron glass system can be understood in terms of the spectrum of a matrix describing the relaxation of the system close to a metastable state. The model focused on the electron glass system, but its generality was demonstrated on various other examples. Here, we study the noise spectrum in the same framework. We obtain a remarkable relation between the spectrum of relaxation rates $\lambda$ described by the distribution function $P(\lambda) \sim 1/\lambda$ and the $1/f$ noise in the fluctuating occupancies of the localized electronic sites. This noise can be observed using local capacitance measurements. We confirm our analytic results using numerics, and also show how the Onsager symmetry is fulfilled in the system.