Superconductivity of hexagonal heavily-boron doped silicon carbide

TL;DR

This paper investigates the superconducting properties of heavily boron-doped silicon carbide, focusing on specific heat measurements of different polytypes, revealing insights into their superconducting behavior and phase characteristics.

Contribution

It provides the first detailed specific heat analysis of boron-doped silicon carbide, highlighting differences between cubic and hexagonal phases and their superconducting properties.

Findings

Both samples show BCS-like and power-law behaviors in specific heat.

Hexagonal SiC:B exhibits type-I superconductivity.

Superconducting characteristics depend on crystal phase composition.

Abstract

In 2004 the discovery of superconductivity in heavily boron-doped diamond (C:B) led to an increasing interest in the superconducting phases of wide-gap semiconductors. Subsequently superconductivity was found in heavily boron-doped cubic silicon (Si:B) and recently in the stochiometric ''mixture'' of heavily boron-doped silicon carbide (SiC:B). The latter system surprisingly exhibits type-I superconductivity in contrast to the type-II superconductors C:B and Si:B. Here we will focus on the specific heat of two different superconducting samples of boron-doped SiC. One of them contains cubic and hexagonal SiC whereas the other consists mainly of hexagonal SiC without any detectable cubic phase fraction. The electronic specific heat in the superconducting state of both samples SiC:B can be described by either assuming a BCS-type exponentional temperature dependence or a power-law behavior.