Kinetic planar resonators from strongly disordered ultra-thin MoC superconducting films investigated by transmission line spectroscopy

TL;DR

This study uses broadband transmission line spectroscopy to analyze GHz-range resonances in disordered MoC superconducting films, revealing their temperature dependence and eigenmodes, which can inform filter design or resonance elimination.

Contribution

It introduces a non-contact spectroscopy method to probe disordered superconductor resonators and relates the resonances to the complex conductivity and density of states.

Findings

Resonances are characterized by Dynes broadening parameters.

Eigenmodes are visualized using EM modeling.

Resonance behavior depends on temperature and disorder.

Abstract

"The non-contact broadband transmission line flip-chip spectroscopy technique is utilized to probe resonances of mm-sized square kinetic planar resonators made from strongly disordered molybdenum carbide films, in the GHz frequency range. The temperature dependence of the resonances was analyzed by the complex conductivity of disordered superconductor, as proposed in Ref. arXiv:1407.2402 , which involves the Dynes superconducting density of states. The obtained Dynes broadening parameters relate reasonably to the ones estimated from scanning tunneling spectroscopy measurements. The eigenmodes of the kinetic planar 2D resonator were visualized by EM model in Sonnet software. The proper understanding of the nature of these resonances can help to eliminate them, or utilize them e.g. as filters."