Superconductivity in Breathing Kagome-Structured C14 Laves Phase XOs2(X = Zr, Hf)

TL;DR

This paper reports the discovery of type-II superconductivity in breathing Kagome-structured C14 Laves phase compounds ZrOs2 and HfOs2, with critical temperatures around 2.7-2.9 K, and analyzes their structural and electronic properties.

Contribution

It provides the first detailed investigation of superconductivity in breathing Kagome C14 Laves phase compounds ZrOs2 and HfOs2, revealing their weakly coupled BCS superconducting nature.

Findings

ZrOs2 and HfOs2 exhibit type-II superconductivity.

Critical temperatures are approximately 2.9 K and 2.7 K.

Weak electron-phonon coupling indicates BCS superconductivity.

Abstract

Recently, the emergence of superconductivity in kagome metals has generated significant interest due to its interaction with flat bands and topological electronic states, which exhibit a range of unusual quantum characteristics. This study thoroughly investigates largely unexplored breathing Kagome structure C14 laves phase compounds XOs$_{2}$ (X = Zr, Hf) by XRD, electrical transport, magnetization, and specific heat measurements. Our analyses confirm the presence of the MgZn$_{2}$-type structure in ZrOs$_{2}$ and HfOs$_{2}$ compounds, exhibiting type-II superconductivity with critical temperature (T$_{C}$) values of 2.90(3) K and 2.69(6) K, respectively. Furthermore, specific heat measurements and an electron-phonon coupling constant suggest the presence of weakly coupled BCS superconductivity in both compounds.