# Fluctuation spectroscopy as a probe of granular superconducting diamond films

## TL;DR

This paper uses fluctuation spectroscopy to analyze resistance data in boron-doped nanocrystalline diamond films, revealing dimensional crossovers and tunneling energies, advancing understanding of granular superconductors.

## Contribution

It demonstrates how fluctuation spectroscopy can be used to probe the properties and dimensional crossovers in granular superconducting diamond films.

## Key findings

- Identification of three distinct scaling regions: 3D intragrain, quasi-0D, and 3D intergrain.
- Determination of tunneling and Thouless energies for each film.
- Confirmation of theoretical predictions of dimensional crossovers in granular superconductors.

## Abstract

We present resistance versus temperature data for a series of boron-doped nanocrystalline diamond films whose grain size is varied by changing the film thickness. Upon extracting the fluctuation conductivity near to the critical temperature we observe three distinct scaling regions -- 3D intragrain, quasi-0D, and 3D intergrain -- in confirmation of the prediction of Lerner, Varlamov and Vinokur. The location of the dimensional crossovers between these scaling regions allows us to determine the tunnelling energy and the Thouless energy for each film. This is a demonstration of the use of \emph{fluctuation spectroscopy} to determine the properties of a superconducting granular system.