2025/04/10 by Nikita Sharma, Jörg Link, Sharma, Nikita +17
Engineering · #Advanced Materials Characterization Techniques #Alloy #Critical field #Fermi level #High Entropy Alloys Studies #High-temperature superconductivity #Intermetallics and Advanced Alloy Properties #Isotropy #Paramagnetism #Pauli exclusion principle #Superconductivity
paper · pdf · doi:10.48550/arxiv.2504.08124
published in arXiv (Cornell University) (Cornell University)
openalex publication_date 2025/04/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
High entropy alloy superconductors represent a unique blend of advanced material systems and quantum physics, offering significant potential for advancing superconducting technologies. In this study, we report a detailed theoretical and experimental investigation of high entropy alloy superconductors Ta0.2Nb0.2V0.2Ti0.2X0.2 (X = Zr and Hf). Our study unveils that both the materials crystallize in a body-centered cubic structure (space group: I m -3 m) and exhibit bulk superconductivity with a superconducting onset temperature of (Tonset C ) of 5 K for X = Hf and 6.19 K for X = Zr sample. Our detailed analysis, including magnetization, resistivity, heat capacity measurements, and density functional theory (DFT) calculations indicates moderately coupled isotropic s-wave superconductivity in these materials. Our DFT results find significant spectral weight at the Fermi energy and phonon spectra is free of imaginary modes, confirming the dynamical stability and metallic nature of these alloys. Remarkably, we have observed a high upper critical field (HC2(0)) surpassing the Pauli paramagnetic limit for the X = Hf sample and explained it on the basis of the increased spin-orbit coupling in the structure. Ta0.2Nb0.2V0.2Ti0.2Zr0.2, on the other hand, shows a conventional HC2 behaviour. With the dynamical stability of these alloys, excellent normal state metallic nature, high micro-hardness, and high upper critical field, these samples emerge as potential candidates for future applications in superconducting devices.