Supercapacitance and superinductance of TiN and NbTiN films in the vicinity of superconductor-to-insulator transition

A Yu Mironov; D M Silevitch; S V Postolova; M V Burdastyh; T Proslier; T I Baturina; T F Rosenbaum; V M Vinokur

doi:10.1038/s41598-021-95530-5

Supercapacitance and superinductance of TiN and NbTiN films in the vicinity of superconductor-to-insulator transition

Sci Rep. 2021 Aug 10;11(1):16181. doi: 10.1038/s41598-021-95530-5.

Authors

A Yu Mironov¹, D M Silevitch², S V Postolova¹, M V Burdastyh^{1

3}, T Proslier⁴, T I Baturina¹, T F Rosenbaum², V M Vinokur^{5

6}

Affiliations

¹ Rzhanov Institute of Semiconductor Physics SB RAS, 13 Lavrentjev Avenue, Novosibirsk, Russia, 630090.
² Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA, 91125, USA.
³ Novosibirsk State University, Pirogova str. 2, Novosibirsk, Russia, 630090.
⁴ Institut de Recherches sur les lois Fundamentales de L'univers, Commissariat de L'énergie Atomique et aux Énergies Renouvelables-Saclay, Gif-sur-Yvette, France.
⁵ Terra Quantum AG, St. Gallerstrasse 16A, 9400, Rorschach, Switzerland. vmvinokour@gmail.com.
⁶ Physics Department, City College of the City University of New York, 160 Convent Ave, New York, NY, 10031, USA. vmvinokour@gmail.com.

Abstract

We investigate the low-temperature complex impedance of disordered insulating thin TiN and NbTiN films in the frequency region 400 Hz-1 MHz in close proximity to the superconductor-insulator transition (SIT). The frequency, temperature, and magnetic field dependencies of the real and imaginary parts of the impedance indicate that in full accord with the theoretical predictions and earlier observations, the films acquire self-induced electronic granularity and become effectively random arrays of superconducting granules coupled via Josephson links. Accordingly, the inductive component of the response is due to superconducting droplets, while the capacitive component results from the effective Josephson junctions capacitances. The impedance crosses over from capacitive to inductive behavior as films go across the transition.