The influence of spin orbit interaction on phonons and superconductivity in the noncentrosymmetric superconductors LaPt<inf>3</inf>Si and LaPtSi<inf>3</inf>
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Reason for embargo
We have performed ab initio study of structural, electronic, vibrational and electron-phonon interaction properties of LaPt3 Si and LaPtSi3 by employing the density functional theory, a linear-response formalism, and the plane-wave pseudopotential method. The electronic structure, phonon dispersion relations and the Eliashberg spectral function for these materials have been examined with and without the inclusion of spin-orbit interaction (SOI). Our electron-phonon interaction results reveal that the influence of spin-orbit interaction on phonons and superconductivity in these noncentrosymmetric superconductors is very small. Thus, we can conclude that a mixing of the spin-singlet and the spin-triplet components in these superconductors is weak and the spin-singlet Cooper pairs dominate. By integrating the Eliashberg spectral function α2F(ω), the average electron-phonon coupling parameter λ is obtained to be 0.470 for LaPt3 Si and 0.488 for LaPtSi3, indicating these to be weak-coupling BCS superconductors. Using an acceptable value of μ∗ = 0.13 for the effective Coulomb repulsion parameter, the superconducting critical temperature Tc is calculated to be 0.67 K for LaPt3 Si and 1.39 K for LaPtSi3, in good accordance with experimental values of 0.65 K and 1.52 K, respectively.
This work was supported by the Scientific and Technical Research Council of Turkey (TÜBİTAK) (Project Number MFAG-115F135). Some of the calculations for this project were carried out using the computing facilities on the Intel Nehalem (i7) cluster (ceres) in the School of Physics, University of Exeter, United Kingdom.
This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.
Vol. 86, July 2017, pp. 1 - 10