Superconductivity of Ta34Nb33Hf8Zr14Ti11 high entropy alloy from first principles calculations

• Published in: Physica status solidi. PSS-RRL. Rapid research letters 2016-05, Vol.10 (5), p.415-419
• Main Authors: Jasiewicz, K., Wiendlocha, B., Korbeń, P., Kaprzyk, S., Tobola, J.
• Format: Article
• Language: English
• Subjects: Approximation; disorder; electronic structure; Entropy; first principles; high-entropy alloys; Superconductivity; Ta34Nb33Hf8Zr14Ti11
• ISSN: 1862-6254; 1862-6270
• DOI: 10.1002/pssr.201600056

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) Superconductivity in the first superconducting high entropy alloy (HEA) is studied basing on electronic structure calculations within the Korringa–Kohn–Rostoker method and the coherent potential approximation (KKR‐CPA). The electron–phonon coupling constant λ ≅ 1 is computed, resulting in the critical temperature in the range 5–15 K, depending on the value of the Coulomb pseudopotential parameter. This supports the electron–phonon coupling mechanism of the superconductivity in the studied system.