Effect of boron dimers on the superconducting critical temperature in boron-doped diamond

TL;DR

This study investigates how attractive boron correlations influence the superconducting critical temperature in boron-doped diamond, revealing that such correlations decrease the density of states at the Fermi level and may explain experimental variations.

Contribution

It introduces a theoretical approach combining the McMillan formula and dynamical cluster approximation to analyze boron correlations' effects on superconductivity in diamond.

Findings

Attractive boron correlations lower the density of states at the Fermi level.

This reduction may account for differences in critical temperatures observed in different film orientations.

The results suggest correlations significantly impact superconducting properties in doped diamond.

Abstract

We study how attractive boron correlations in boron-doped diamond affect the superconducting critical temperature. The critical temperature is obtained from the McMillan formula for strong coupling superconductors with the density of states evaluated in the dynamical cluster approximation. Numerical results for the cluster of $2\times 2\times 2$ atoms show that attractive correlations lower the density of states at the Fermi level. We argue that this might explain experimentally observed differences in critical temperatures of 100 and 111 oriented films.