# Type-I superconductivity in Al$_6$Re

## TL;DR

This paper reports the discovery of Type-I superconductivity in Al$_6$Re, a rhenium aluminide, using various physical measurements, highlighting its significance among compound superconductors and its potential for studying superconductivity mechanisms.

## Contribution

First demonstration of Type-I superconductivity in Al$_6$Re, providing insights into the factors influencing superconductivity in aluminides.

## Key findings

- Al$_6$Re is a Type-I superconductor based on magnetization, ac-susceptibility, and specific-heat data.
- Al$_6$Re's superconductivity contrasts with similar non-superconducting aluminides.
- The study suggests valence electron count and inversion symmetry are key in superconductivity.

## Abstract

While the pure elements tend to exhibit Type-I rather than Type-II superconductivity, nearly all compound superconductors are Type-II, with only a few known exceptions. We report single crystal growth and physical characterization of the rhenium aluminide Al$_6$Re, which we conclude is a Type-I superconductor based on magnetization, ac-susceptibility, and specific-heat measurements. This detection of superconductivity, despite the strong similarity of Al$_6$Re to a family of W and Mo aluminides that do not superconduct, suggests that these aluminides are an ideal testbed for identifying the relative importance of valence electron count and inversion symmetry in determining whether a material will superconduct.