Superconductivity of Ta34Nb33Hf8Zr14Ti11 high entropy alloy from first principles calculations

The Korringa–Kohn–Rostoker method with the coherent potental approximation (KKR-CPA) is applied to study the first superconducting high entropy alloy (HEA) Ta34Nb33Hf8Zr14Ti11 (discovered in 2014 with Tc = 7.3 K), focusing on estimations of the electron–phonon coupling constant λ. The electronic part of λ has been calculated using the rigid muffin-tin approximation (RMTA), while the phonon part has been approximated using average atomic mass and experimental Debye temperature. The estimated λ = 1.16 is close to the value determined from specific heat measurements, λ = 0.98, and suggests rather strong electron–phonon coupling in this material. (© 2016 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim)