Ab initio study of orbital-selective superconductivity in γ-BiPd
Journal
Physical Review B
Journal Volume
112
Journal Issue
21
Start Page
214518
ISSN
2469-9950
2469-9969
Date Issued
2025-12-23
Author(s)
Keshri, Sonu Prasad
Abstract
We investigate the superconducting (SC) properties of experimentally realized γ -BiPd by solving the anisotropic Migdal-Eliashberg equations in conjunction with ab initio relativistic calculations of the electron and phonon band structures as well as electron-phonon coupling (EPC) matrix elements. Our study reveals that γ -BiPd possesses a complex Fermi surface (FS), consisting of two electron pockets and one hole pocket, each characterized by distinct atomic orbitals. Our key finding is that the superconductivity in γ -BiPd is primarily orbital selective, arising from Bi p orbitals, and distributed anisotropically on the FS, although contribution from Pd d orbitals, particularly on the hole pocket, is also discernible. While our results show an anisotropic nature of the k-dependent SC gap △k and EPC strength λk across the FS, calculated superconducting quasiparticle density of states NS spectra exhibit a U-shaped gap and △k distribution forms a single peak, being consistent with the spin-singlet s-wave superconductivity observed in this material. The calculated Tc is ∼ 2.0 K, agreeing in order of magnitude with the experimental value of 3.3 K in γ -BiPd thin films. The predicted EPC-enhanced Sommerfeld coefficient γn of 0.141 mJ/K2 cm3 is similar to the experimental γn value (0.119 mJ/K2 cm3) of the isoelectronic and isostructural Bi(Pd0.5 Pt0.5) alloy.
Publisher
American Physical Society (APS)
Type
journal article