Memory effects in Amorphous Solids below 20 mK

TL;DR

This paper investigates low-temperature memory effects in amorphous solids below 20 mK, revealing a history-dependent capacitance change explained by resonant pair dynamics, extending understanding of glassy dielectric behavior.

Contribution

It reports a novel low-temperature memory effect in amorphous solids and proposes a qualitative model based on resonant pair dynamics to explain it.

Findings

Capacitance decreases by about 10^{-5} during the first DC field sweep below 20 mK.

Subsequent field sweeps show a persistent shift in dielectric constant.

The behavior aligns with predictions from the dipole gap theory and resonant pair dynamics.

Abstract

At temperatures below 1 K, the capacitance of a glass sample changes due to the application of a DC field in accordance with A. Burins dipole gap theory. However, we now report that below 20 mK, during the first sweep cycle of the DC electric field the capacitance is smaller by about $10^{-5}$ compared to any subsequent sweep. Despite this overall shift the field dependence follows the dipole gap predictions. In a subsequent sweep to higher DC fields the dielectric constant drops by about $10^{-5}$ as soon as the applied field is higher than any field previously applied. A picture involving the dynamics of resonant pairs provides a qualitative description of this behavior.