Mo$_{3}$ReRuC: A noncentrosymmetric superconductor formed in the MoReRu-Mo$_{2}$C system

TL;DR

This paper reports the discovery and characterization of Mo$_{3}$ReRuC, a noncentrosymmetric superconductor with strong coupling properties, formed in a new quaternary system, expanding the understanding of noncentrosymmetric superconductors.

Contribution

The study introduces Mo$_{3}$ReRuC as a new noncentrosymmetric superconductor with detailed structural, electronic, and superconducting properties, highlighting its potential in superconductor research.

Findings

Mo$_{3}$ReRuC is a bulk type-II superconductor below 7.7 K.

It exhibits a large specific heat jump indicating strong coupling.

Electronic structure calculations show significant spin-orbit coupling effects.

Abstract

A quaternary compound with the composition Mo$_{3}$ReRuC is obtained in a previously unexplored MoReRu-Mo$_{2}$C system. According to x-ray structural analysis, Mo$_{3}$ReRuC crystallizes in the noncentrosymmetric space group $P$4$_{1}$32 (cubic $\beta$-Mn type structure, $a$ = 6.8107(1) {\AA}). Below 7.7 K, Mo$_{3}$ReRuC becomes a bulk type-II superconductor with an upper critical field close to the Pauli paramagnetic limit. The specific heat data gives a large normalized jump $\Delta$$C_{\rm p}$/$\gamma$$T_{\rm c}$ = 2.3 at $T_{\rm c}$, which points to a strongly coupled superconducting state. First principles calculations show that its electronic states at the Fermi level are mainly contributed by Mo, Re and Ru atoms and strongly increased by the spin-orbit coupling. Our finding suggests that the intermediate phase between alloys and carbides may be a good place to look for $\beta$-Mn type noncentrosymmetric superconductors.