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| Format: | Preprint |
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2024
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| Online Access: | https://arxiv.org/abs/2411.14734 |
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| _version_ | 1866918262261940224 |
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| author | Keshri, Sonu Prasad Guo, Guang-Yu |
| author_facet | Keshri, Sonu Prasad Guo, Guang-Yu |
| contents | We investigate the superconducting (SC) properties of experimentally realised $γ$-BiPd by solving the anisotropic Migdal-Eliashberg equations in conjunction with {\it 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 characterised 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 discernable. While our results show an anisotropic nature of the {\bf k}-dependent SC gap $Δ_{\bf k}$ and EPC strength $λ_{\bf k}$ across the FS, calculated superconducting quasiparticle density of states $N_S$ spectra exhibit a U-shaped gap and $Δ_{\bf k}$ distribution forms a single peak, being consistent with the spin-singlet $s$-wave superconductivity observed in this material. The calculated $T_c$ is $\sim$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 $γ_n$ of $0.141$ mJ/K$^2$cm$^3$ is similar to the experimental $γ_n$ value ($0.119$ mJ/K$^2$cm$^3$) of the isoelectronic and isostructural Bi(Pd$_{0.5}$Pt$_{0.5}$) alloy. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2411_14734 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Ab initio study of orbital-selective superconductivity in $γ$-BiPd Keshri, Sonu Prasad Guo, Guang-Yu Superconductivity We investigate the superconducting (SC) properties of experimentally realised $γ$-BiPd by solving the anisotropic Migdal-Eliashberg equations in conjunction with {\it 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 characterised 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 discernable. While our results show an anisotropic nature of the {\bf k}-dependent SC gap $Δ_{\bf k}$ and EPC strength $λ_{\bf k}$ across the FS, calculated superconducting quasiparticle density of states $N_S$ spectra exhibit a U-shaped gap and $Δ_{\bf k}$ distribution forms a single peak, being consistent with the spin-singlet $s$-wave superconductivity observed in this material. The calculated $T_c$ is $\sim$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 $γ_n$ of $0.141$ mJ/K$^2$cm$^3$ is similar to the experimental $γ_n$ value ($0.119$ mJ/K$^2$cm$^3$) of the isoelectronic and isostructural Bi(Pd$_{0.5}$Pt$_{0.5}$) alloy. |
| title | Ab initio study of orbital-selective superconductivity in $γ$-BiPd |
| topic | Superconductivity |
| url | https://arxiv.org/abs/2411.14734 |