Electron-phonon interaction and superconductivity in hexagonal BaSn₅

Abstract

We have made an extensive study of the electronic band structure and phonon spectrum, and the electron-phonon interaction, in BaSn 5 by employing an ab initio pseudopotential method and a linear response scheme. The Sn atoms are identified to make a significant contribution to the electronic density of states very close to the Fermi energy and to the average electron-phonon coupling parameter. Using the computed value of 0.96 for the average electron-phonon coupling parameter, we evaluate the superconducting critical temperature and the electronic specific heat coefficient are found to be 4.23 K and 12.9 mJ/(molK 2 ), respectively, in good accordance with the corresponding experimental values of 4.4 K and 10.8 mJ/(molK 2 ).

Properties of the Superconducting State in Hexagonal BaSn5

“…and in our case it is equal to 72.92 meV. For BaSn 5 superconductor, the Eliashberg function (α 2 F (Ω )) has been calculated by employing an ab initio pseudopotential method and a linear response scheme in the paper [9]. The maximum phonon frequency (Ω max ) and the electron-phonon coupling constant (λ) are equal to 16.52 meV and 0.96, respectively.…”

“…Real and imaginary part of the order parameter on the real axis for T = 0.6 K. The Eliashberg function[9] is present in the background -the correlation between the course of the order parameter and the spectral function is clearly visible.…”

Exact factorization-based density functional theory of electron-phonon systems

“…The electronic band structure, phonon modes and electron-phonon coupling terms define a BO reference state that contains enough information to evaluate several observables, such as the electron-phonon coupling constant λ and transition temperature T c in conventional superconductors such as MgB 2 , 6-22 electronic band structure renormalization, [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40] and electronic mass enhancement and specific heat. 12,13,18,[41][42][43][44][45][46][47][48][49][50][51][52][53][54] Nevertheless, there is growing interest in capturing nonadiabatic electronphonon effects [55][56][57][58][59][60][61][62][63][64][65][66] by ab initio approaches that ...…”