Dependence of the superconducting transition temperature on the doping level in single crystalline diamond films

TL;DR

This study demonstrates that boron-doped single crystalline diamond films exhibit superconductivity with transition temperatures up to 2.1 K, depending on doping levels, providing new insights into the superconducting behavior of diamond.

Contribution

It provides experimental evidence linking boron doping levels to superconducting transition temperatures in diamond, constraining theoretical models.

Findings

Superconductivity observed in boron-doped diamond at 0.2K to 2.1K.

Critical boron concentration for superconductivity is about 5-7 x 10^20 /cm^3.

The H-T phase diagram was mapped down to 300mK.

Abstract

Homoepitaxial diamond layers doped with boron in the 10^20-10^21 /cm3 range are shown to be type II superconductors with sharp transitions (~0.2K) at temperatures increasing from 0 to 2.1 K with boron contents. The critical concentration for the onset of superconductivity is about 5-7 10^20 /cm3, close to the metal-insulator transition. The H-T phase diagram has been obtained from transport and a.c. susceptibility measurements down to 300mK. These results bring new quantitative constraints on the theoretical models proposed for superconductivity in diamond.