Electronic Structure and Electron-Phonon Coupling Calculations for bcc HEA Superconductors Ta-Nb-Hf-Zr-Ti

Results of the electronic structureElectronic structure and electron-phonon couplingElectron-phonon coupling calculations for the first superconducting HEA, bcc-type Ta \(_{0.34}\) Nb \(_{0.33}\) Hf \(_{0.08}\) Zr \(_{0.14}\) Ti \(_{0.11}\) and its variant (TaNb) \(_{0.67}\) (HfZrTi) \(_{0.33}\) are reviewed. The Korringa-Kohn-Rostoker method with the coherent potential approximationCoherent potential approximation is used to calculate the electronic structureElectronic structure in the presence of the chemical disorder. The electron-phonon couplingElectron-phonon coupling constant \(\lambda \) is calculated using the rigid muffin tin approximation. Next, the electronic structureElectronic structure, phonons and electron-phonon coupling are calculated using the virtual crystal approximation, which allows us to discuss the effects of disorder on the properties of the HEA. The analysis suggested that disorder influences the phonon structurePhonon structure more strongly than the electronic structure. The effect of external pressure on electron-phonon couplingElectron-phonon coupling and superconductivity is studied, and the results correctly reproduce the observed increase in \(T_c\) . Finally, we studied the local distortions of the crystal structure and found that they tended to decrease \(\lambda \) .