Superconductivity in the high-entropy ceramics Ti0.2Zr0.2Nb0.2Mo0.2Ta0.2Cx with possible nontrivial band topology

TL;DR

This study reports the discovery of superconductivity and potential topological properties in high-entropy ceramics Ti0.2Zr0.2Nb0.2Mo0.2Ta0.2Cx, combining experimental results and first-principles calculations to explore their electronic structure and robustness under pressure.

Contribution

First demonstration of superconductivity and possible nontrivial band topology in high-entropy ceramics Ti0.2Zr0.2Nb0.2Mo0.2Ta0.2Cx, supported by experimental and computational analysis.

Findings

Bulk type-II superconductivity with Tc around 4 K and 2.65 K.

Superconductivity remains stable under high pressure up to 82.5 GPa.

Presence of Dirac-like points indicating potential topological superconductivity.

Abstract

Topological superconductors have drawn significant interest from the scientific community due to the accompanying Majorana fermions. Here, we report the discovery of electronic structure and superconductivity in high-entropy ceramics Ti0.2Zr0.2Nb0.2Mo0.2Ta0.2Cx (x = 1 and 0.8) combined with experiments and first-principles calculations. The Ti0.2Zr0.2Nb0.2Mo0.2Ta0.2Cx high-entropy ceramics show bulk type-II superconductivity with Tc about 4.00 K (x = 1) and 2.65 K (x = 0.8), respectively. The specific heat jump is equal to 1.45 (x = 1) and 1.52 (x = 0.8), close to the expected value of 1.43 for the BCS superconductor in the weak coupling limit. The high-pressure resistance measurements show that a robust superconductivity against high physical pressure in Ti0.2Zr0.2Nb0.2Mo0.2Ta0.2C, with a slight Tc variation of 0.3 K within 82.5 GPa. Furthermore, the first-principles calculations indicate that the Dirac-like point exists in the electronic band structures of Ti0.2Zr0.2Nb0.2Mo0.2Ta0.2C, which is potentially a topological superconductor. The Dirac-like point is mainly contributed by the d orbitals of transition metals M and the p orbitals of C. The high-entropy ceramics provide an excellent platform for the fabrication of novel quantum devices, and our study may spark significant future physics investigations in this intriguing material.