# Microwave dynamics of high aspect ratio superconducting nanowires studied using self-resonance

## Abstract

We study the microwave impedance of extremely high aspect ratio (length/width ≈ 5000) superconducting niobium nitride nanowires. The nanowires are fabricated in a compact meander geometry that is in series with the center conductor of a 50 Ω coplanar waveguide transmission line. The transmission coefficient of the sample is measured up to 20 GHz. At high frequency, a peak in the transmission coefficient is seen. Numerical simulations show that this is a half-wave resonance along the length of the nanowire, where the nanowire acts as a high impedance, slow wave transmission line. This resonance sets the upper frequency limit for these nanowires as inductive elements. Fitting simulations to the measured resonance enables a precise determination of the nanowire's complex sheet impedance at the resonance frequency. The real part is a measure of dissipation, while the imaginary part is dominated by kinetic inductance. We characterize the dependence of the sheet resistance and sheet inductance on both temperature and current and compare the results to recent theoretical predictions for disordered superconductors. These results can aid in the understanding of high frequency devices based on superconducting nanowires. They may also lead to the development of novel superconducting devices such as ultra-compact resonators and slow-wave structures.

- Authors:

- Department of Physics, University of North Florida, Jacksonville, Florida 32224 (United States)
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

- Publication Date:

- OSTI Identifier:
- 22596812

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Journal of Applied Physics; Journal Volume: 119; Journal Issue: 23; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ASPECT RATIO; COMPARATIVE EVALUATIONS; COMPUTERIZED SIMULATION; GHZ RANGE 01-100; IMPEDANCE; INDUCTANCE; LENGTH; MICROWAVE RADIATION; NANOWIRES; NIOBIUM NITRIDES; RESONANCE; RESONATORS; SUPERCONDUCTING DEVICES; SUPERCONDUCTORS; WAVEGUIDES

### Citation Formats

```
Santavicca, Daniel F., E-mail: daniel.santavicca@unf.edu, Adams, Jesse K., Grant, Lierd E., McCaughan, Adam N., and Berggren, Karl K.
```*Microwave dynamics of high aspect ratio superconducting nanowires studied using self-resonance*. United States: N. p., 2016.
Web. doi:10.1063/1.4954068.

```
Santavicca, Daniel F., E-mail: daniel.santavicca@unf.edu, Adams, Jesse K., Grant, Lierd E., McCaughan, Adam N., & Berggren, Karl K.
```*Microwave dynamics of high aspect ratio superconducting nanowires studied using self-resonance*. United States. doi:10.1063/1.4954068.

```
Santavicca, Daniel F., E-mail: daniel.santavicca@unf.edu, Adams, Jesse K., Grant, Lierd E., McCaughan, Adam N., and Berggren, Karl K. Tue .
"Microwave dynamics of high aspect ratio superconducting nanowires studied using self-resonance". United States.
doi:10.1063/1.4954068.
```

```
@article{osti_22596812,
```

title = {Microwave dynamics of high aspect ratio superconducting nanowires studied using self-resonance},

author = {Santavicca, Daniel F., E-mail: daniel.santavicca@unf.edu and Adams, Jesse K. and Grant, Lierd E. and McCaughan, Adam N. and Berggren, Karl K.},

abstractNote = {We study the microwave impedance of extremely high aspect ratio (length/width ≈ 5000) superconducting niobium nitride nanowires. The nanowires are fabricated in a compact meander geometry that is in series with the center conductor of a 50 Ω coplanar waveguide transmission line. The transmission coefficient of the sample is measured up to 20 GHz. At high frequency, a peak in the transmission coefficient is seen. Numerical simulations show that this is a half-wave resonance along the length of the nanowire, where the nanowire acts as a high impedance, slow wave transmission line. This resonance sets the upper frequency limit for these nanowires as inductive elements. Fitting simulations to the measured resonance enables a precise determination of the nanowire's complex sheet impedance at the resonance frequency. The real part is a measure of dissipation, while the imaginary part is dominated by kinetic inductance. We characterize the dependence of the sheet resistance and sheet inductance on both temperature and current and compare the results to recent theoretical predictions for disordered superconductors. These results can aid in the understanding of high frequency devices based on superconducting nanowires. They may also lead to the development of novel superconducting devices such as ultra-compact resonators and slow-wave structures.},

doi = {10.1063/1.4954068},

journal = {Journal of Applied Physics},

number = 23,

volume = 119,

place = {United States},

year = {Tue Jun 21 00:00:00 EDT 2016},

month = {Tue Jun 21 00:00:00 EDT 2016}

}