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 \lambda. Electronic part of \lambda 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 \lambda = 1.16 is close to the value determined from specific heat measurements, \lambda = 0.98, and suggests rather strong electron-phonon coupling in this material.