SKM 2021 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 22: Poster Session: Disordered and Granular Superconductors: Fundamentals and Applications in Quantum Technology
TT 22.4: Poster
Thursday, September 30, 2021, 13:30–16:00, P
Dielectric properties of amorphous indium oxide on the insulating side of the superconductor-insulator transition — Nikolaj Ebensperger1, Paul Kugler1, •Anastasia Bauernfeind1, Martin Dressel1, Benjamin Sacépé2, Mikhail Feigel'man3, and Marc Scheffler1 — 11. Physikalisches Institut, University of Stuttgart, Stuttgart, Germany — 2Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, Grenoble, France — 3L.D. Landau Institute for Theoretical Physics, Chernogolovka, Russia
Amorphous indium oxide (a:InO) plays a prominent role in the study of strongly disordered superconductors. In particular, the disorder-driven transition (SIT) between superconducting and insulating states can be realized. Compared to the superconducting side of the SIT, the insulating side has been explored much less experimentally due to the lack of appropriate experimental means. Here we present dielectric measurements on insulating a:InO, performed at GHz frequencies and at temperatures down to the mK regime, on a set of samples with varying disorder. We obtain the real and imaginary parts of the dielectric function (corresponding to frequency-dependent conductivity) as function of disorder, temperature, and frequency. We analyse these data based on theory for hopping in disordered systems, and we trace the evolution of the dielectric function, e.g. the increase of its real part upon approaching the SIT.