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Main Authors: Grenet, Thierry, Delahaye, Julien
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2507.16016
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author Grenet, Thierry
Delahaye, Julien
author_facet Grenet, Thierry
Delahaye, Julien
contents In this article, we explore the temperature dependence of the electrical glassy dynamics in insulating amorphous indium oxide (a-InOx) and granular Al films. We use non-isothermal gate voltage protocols, which can reveal changes in the dynamics induced by the temperature, when logarithmic relaxations devoid of characteristic times are at work. We demonstrate that, contrary to almost 20 years of opposite belief, the dynamics of amorphous indium oxide films in the liquid helium temperature range is thermally activated, i.e. it slows down under cooling and accelerates upon heating. Amorphous indium oxide thus adds to the list of glassy disordered systems in which we already demonstrated thermal activation, which includes granular Al and amorphous NbxSi1-x films. Moreover, measurements up to 40 K in a-InOx and granular Al films reveal the close similarity between the two systems and a very anomalous character of the thermal activation, with an effective activation energy increasing with T as T^2 . We so far have no explanation for it. Its further study and understanding may be important for the physics of electron glasses.
format Preprint
id arxiv_https___arxiv_org_abs_2507_16016
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Anomalous thermal activation of the electron glass dynamics in a-InOx and granular aluminum
Grenet, Thierry
Delahaye, Julien
Disordered Systems and Neural Networks
In this article, we explore the temperature dependence of the electrical glassy dynamics in insulating amorphous indium oxide (a-InOx) and granular Al films. We use non-isothermal gate voltage protocols, which can reveal changes in the dynamics induced by the temperature, when logarithmic relaxations devoid of characteristic times are at work. We demonstrate that, contrary to almost 20 years of opposite belief, the dynamics of amorphous indium oxide films in the liquid helium temperature range is thermally activated, i.e. it slows down under cooling and accelerates upon heating. Amorphous indium oxide thus adds to the list of glassy disordered systems in which we already demonstrated thermal activation, which includes granular Al and amorphous NbxSi1-x films. Moreover, measurements up to 40 K in a-InOx and granular Al films reveal the close similarity between the two systems and a very anomalous character of the thermal activation, with an effective activation energy increasing with T as T^2 . We so far have no explanation for it. Its further study and understanding may be important for the physics of electron glasses.
title Anomalous thermal activation of the electron glass dynamics in a-InOx and granular aluminum
topic Disordered Systems and Neural Networks
url https://arxiv.org/abs/2507.16016