Electronic structure, electron-phonon coupling and superconductivity of isotypic noncentrosymmetric crystals Li$_2$Pd$_3$B and Li$_2$Pt$_3$B

S. K. Bose; E. S. Zijlstra

doi:10.1016/j.physc.2005.08.006

paper

Electronic structure, electron-phonon coupling and superconductivity of isotypic noncentrosymmetric crystals Li $_{2}$ Pd $_{3}$ B and Li $_{2}$ Pt $_{3}$ B

arXiv:cond-mat/0507278 · doi:10.1016/j.physc.2005.08.006

Abstract

Electronic structure of recently discovered isotypic ternary borides Li $_{2}$ Pd $_{3}$ B and Li $_{2}$ Pt $_{3}$ B, with noncentrosymmetric crystal structures, is studied with a view to understanding their superconducting properties. Estimates of the Fermi-surface averaged electron-phonon matrix element and Hopfield parameter are obtained in the rigid ion approximation of Gaspari and Gyorffy [Phys. Rev. Lett. {\bf 28} (1972) 801]. The contribution of the lithium atoms to the electron-phonon coupling is found to be negligible, while both boron and palladium atoms contribute equally strongly to the Hopfield parameter. There is a significant transfer of charge from lithium, almost the entire valence charge, to the B-Pd(Pt) complex. The electronic structure and superconducting properties of Li $_{2}$ Pd $_{3}$ B, thus, can be understood from the viewpoint of the compound being composed of a connected array of B-Pd tetrahedra decoupled from the backbone of Li atoms, which are connected by relatively short bonds. Our results suggest that conventional s-wave electron-phonon interaction without explicit consideration of SO coupling can explain qualitatively the observed $T_{c}$ in Li $_{2}$ Pd $_{3}$ B. However, such an approach is likely to fail to describe superconductivity in Li $_{2}$ Pt $_{3}$ B.

14 pages, 4 figures An erroneous statement following Eq. 6 in version 1 has been deleted. A statement regarding the possible inadequacy of Eq. 6 has been added following Eq. 6. At two places in the discussion Refs. 37,39 has been changed to 37-39, as it should be

Electronic structure, electron-phonon coupling and superconductivity of isotypic noncentrosymmetric crystals Li $_{2}$ Pd $_{3}$ B and Li $_{2}$ Pt $_{3}$ B

Abstract

References in corpus (10)

Cited by in corpus (7)

Electronic structure, electron-phonon coupling and superconductivity of isotypic noncentrosymmetric crystals Li2​Pd3​B and Li2​Pt3​B

Abstract

References in corpus (10)

Cited by in corpus (7)

Electronic structure, electron-phonon coupling and superconductivity of isotypic noncentrosymmetric crystals Li $_{2}$ Pd $_{3}$ B and Li $_{2}$ Pt $_{3}$ B