The structure of the superconducting high-pressure phase of Sc$_3$CoC$_4$

TL;DR

This study reveals the structural details of the superconducting phase in Sc3CoC4 under high pressure, showing that superconductivity persists despite the presence of Peierls-type distortions, challenging common assumptions about low-dimensional superconductors.

Contribution

The paper provides the first detailed high-pressure structural analysis of Sc3CoC4, linking subtle structural changes to pressure-enhanced superconductivity and demonstrating that distortions are not necessarily suppressed in the superconducting phase.

Findings

Structural differences between ambient and high-pressure phases identified.

Superconductivity coexists with Peierls-type distortions.

Suppression of distortions is not essential for superconductivity in this material.

Abstract

We investigate pressure-induced structural changes to the Peierls-type distorted low-temperature phase of the low-dimensional Sc$_3$CoC$_4$ as a possible origin of its pressure-enhanced superconductivity. By means of cryogenic high-pressure x-ray diffraction experiments we could reveal subtle, but significant structural differences between the low-temperature phase at ambient and elevated pressures. We could thus establish the structure of the superconducting phase of the title compound which interestingly still shows the main features of the Peierls-type distorted low-temperature phase. This indicates that in contrast to other low-dimensional materials a suppression of periodic structural distortions is no prerequisite for superconducitivity in the transition metal carbide.