Ultrahigh-inductance materials from spinodal decomposition

TL;DR

This paper introduces a novel method using spinodal decomposition to significantly increase the kinetic inductance of superconducting nitrides, enhancing their suitability for quantum circuits without increasing microwave loss.

Contribution

It demonstrates for the first time that spinodal decomposition can induce an insulator-to-superconductor transition with greatly increased disorder, boosting inductance by 2-3 orders of magnitude.

Findings

Kinetic inductance increased by 2-3 orders of magnitude.

Spinodal decomposition triggers insulator-to-superconductor transition.

Low microwave loss maintained despite high disorder.

Abstract

Disordered superconducting nitrides with kinetic inductance have long been considered a leading material candidate for high-inductance quantum-circuit applications. Despite continuing efforts in reducing material dimensions to increase the kinetic inductance and the corresponding circuit impedance, it becomes a fundamental challenge to improve further without compromising material qualities. To this end, we propose a method to drastically increase the kinetic inductance of superconducting materials via spinodal decomposition while keeping a low microwave loss. We use epitaxial Ti\textsubscript{0.48}Al\textsubscript{0.52}N as a model system, and for the first time demonstrate the utilization of spinodal decomposition to trigger the insulator-to-superconductor transition with a drastically enhanced material disorder. The measured kinetic inductance has increased by 2-3 orders of magnitude compared with all the best reported disordered superconducting nitrides. Our work paves the way for substantially enhancing and deterministically controlling the inductance for advanced superconducting quantum circuits.