Absence of superconductivity in topological metal ScInAu$_2$

TL;DR

This study investigates the reported superconductivity in ScInAu$_2$, finding that high-quality samples do not exhibit superconductivity and that previous reports likely resulted from elemental indium contamination.

Contribution

The paper clarifies that superconductivity in ScInAu$_2$ is non-intrinsic and attributes previous observations to elemental indium contamination, challenging prior claims.

Findings

High-quality polycrystalline ScInAu$_2$ lacks superconductivity.

Superconductivity in earlier samples is due to elemental indium.

No intrinsic topological superconductivity observed in ScInAu$_2$.

Abstract

The Heusler compound ScInAu$_2$ was previously reported to have a superconducting ground state with a critical temperature of 3.0 K. Recent high throughput calculations have also predicted that the material harbors a topologically non-trivial band structure similar to that reported for beta-PdBi$_2$. In an effort to explore the interplay between the superconducting and topological properties properties, electrical resistance, magnetization, and x-ray diffraction measurements were performed on polycrystalline ScInAu$_2$. The data reveal that high-quality polycrystalline samples lack the super-conducting transition present samples that have not been annealed. These results indicate the earlier reported superconductivity is non-intrinsic. Several compounds in the Au-In-Sc ternary phase space (ScAu$_2$, ScIn$_3$, and ScInAu$_2$) were explored in an attempt to identify the secondary phase responsible for the non-intrinsic superconductivity. The results suggest that elemental In is responsible for the reported superconductivity in ScInAu$_2$.