Superconducting pairing symmetry in MoTe$_{2}$

TL;DR

This study investigates the pairing symmetry in MoTe₂, revealing that despite structural complexities, the superconductivity is consistent with conventional s^{++} pairing rather than topological s^{+-} pairing.

Contribution

It provides the most accurate phase diagram for MoTe₂ and clarifies the pairing symmetry as conventional s^{++} through detailed resistivity analysis under pressure.

Findings

Superconducting transition temperature remains unaffected by disorder.

Pressure favors superconductivity and suppresses structural transition.

Data supports conventional s^{++} pairing symmetry.

Abstract

Topological superconductors have long been sought for their potential use in quantum computing. The type-II Weyl semimetal MoTe$_{2}$ is an obvious candidate, exhibiting a superconducting state below 500 mK at ambient pressure, but the question remains whether the pairing is conventional $s^{++}$ or topological $s^{+-}$. The application of external pressure favors the superconducting state in MoTe$_{2}$ and suppresses the structural transition from $1T'$ to $T_{d}$. The competition between the two structures leads to a mixed phase that strongly enhances the disorder present in the system, remarkably without affecting the superconducting transition temperature, in contrast to the expectation of $s^{+-}$ pairing superconductivity. Our thorough analysis of the electrical and Hall resistivities as a function of pressure yields the most accurate temperature-pressure phase diagram available to date for MoTe$_{2}$ and a detailed view of the relationship between disorder and superconductivity, supporting a conventional $s^{++}$ pairing symmetry.