Nonequilibrium interpretation of DC properties of NbN superconducting hot electron bolometers

TL;DR

This paper offers a nonequilibrium superconductivity-based interpretation of NbN superconducting hot-electron bolometers' DC properties, aiding device characterization and understanding spatial variations.

Contribution

It introduces a physically consistent nonequilibrium model for NbN HEB mixers' DC behavior, clarifying how to extract physical information from measurements.

Findings

Resistive transition analysis reveals key physical parameters.

DC I-V characteristics inform device optimization.

Spatial variation impacts device performance and variability.

Abstract

We present a physically consistent interpretation of the dc electrical properties of niobiumnitride (NbN)-based superconducting hot-electron bolometer (HEB-) mixers, using concepts of nonequilibrium superconductivity. Through this we clarify what physical information can be extracted from the resistive transition and the dc current-voltage characteristics, measured at suitably chosen temperatures, and relevant for device characterization and optimization. We point out that the intrinsic spatial variation of the electronic properties of disordered superconductors, such as NbN, leads to a variation from device to device.