Spatially-Correlated Microstructure and Superconductivity in Polycrystalline Boron-Doped Diamond

TL;DR

This study investigates the relationship between microstructure and superconductivity in boron-doped diamond films, revealing how granular structure influences local superconducting properties and gap behavior.

Contribution

It provides new insights into how microstructural features correlate with superconducting characteristics at the nanoscale in boron-doped diamond.

Findings

Superconductivity varies with granular structure.

Intrinsic grains follow BCS superconductivity.

Proximity effect influences some grains.

Abstract

Scanning tunneling spectroscopies are performed below 100~mK on nano-crystalline boron-doped diamond films characterized by Transmission Electron Microscopy and transport measurements. We demonstrate a strong correlation between the local superconductivity strength and the granular structure of the films. The study of the spectral shape, amplitude and temperature dependence of the superconductivity gap enables us to differentiate intrinsically superconducting grains that follow the BCS model, from grains showing a different behavior involving the superconducting proximity effect.