Field-induced structural aging in glasses at ultra low temperatures

TL;DR

This study investigates how strong electric bias fields induce long-lasting structural changes in glasses at ultra-low temperatures, revealing a new decay mechanism beyond existing models.

Contribution

It introduces a new mechanism involving bias field-induced structural rearrangements of tunneling states that decay via quantum tunneling, extending current models.

Findings

Long time decay of dielectric response in Mylar and BK7 glasses.

Existing models explain Mylar but not BK7; new mechanism accounts for both.

Decay times are temperature independent, indicating a novel process.

Abstract

In non-equilibrium experiments on the glasses Mylar and BK7, we measured the excess dielectric response after the temporary application of a strong electric bias field at mK--temperatures. A model recently developed describes the observed long time decays qualitatively for Mylar [PRL 90, 105501, S. Ludwig, P. Nalbach, D. Rosenberg, D. Osheroff], but fails for BK7. In contrast, our results on both samples can be described by including an additional mechanism to the mentioned model with temperature independent decay times of the excess dielectric response. As the origin of this novel process beyond the "tunneling model" we suggest bias field induced structural rearrangements of "tunneling states" that decay by quantum mechanical tunneling.