Superconductivity in the High-Entropy Ceramics Ti_0.2 Zr_0.2 Nb_0.2 Mo_0.2 Ta_0.2 C_x with Possible Nontrivial Band Topology.

ABSTRACT: Topological superconductors have drawn significant interest from the scientific community due to the accompanying Majorana fermions. Here, the discovery of electronic structure and superconductivity (SC) in high-entropy ceramics Ti_0.2 Zr_0.2 Nb_0.2 Mo_0.2 Ta_0.2 C_x (x = 1 and 0.8) combined with experiments and first-principles calculations is reported. The Ti_0.2 Zr_0.2 Nb_0.2 Mo_0.2 Ta_0.2 C_x high-entropy ceramics show bulk type-II SC with T_c ≈ 4.00 K (x = 1) and 2.65 K (x = 0.8), respectively. The specific heat jump (∆C/γT_c ) 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 a robust SC against high physical pressure in Ti_0.2 Zr_0.2 Nb_0.2 Mo_0.2 Ta_0.2 C, with a slight T_c 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 Ti_0.2 Zr_0.2 Nb_0.2 Mo_0.2 Ta_0.2 C, 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 the study may spark significant future physics investigations in this intriguing material.

SUBMITTER: Zeng L 

PROVIDER: S-EPMC10837384 | biostudies-literature | 2024 Feb

REPOSITORIES: biostudies-literature