skip to main content

SciTech ConnectSciTech Connect

Title: A comparative ab initio study of superconductivity in the body centered tetragonal YC{sub 2} and LaC{sub 2}

Ab initio studies of the electronic band structure and phonon dispersion relations, using the planewave pseudopotential method and the density functional theory, have been made for the superconducting materials YC{sub 2} and LaC{sub 2}. Differences in the phonon spectrum and density of states both in the acoustical and optical ranges between these materials are investigated and discussed. By integrating the Eliashberg spectral function α{sup 2}F(ω), the average electron-phonon coupling parameter is found to be λ = 0.55 for YC{sub 2} and 0.54 for LaC{sub 2}, indicating these to be weak-coupling BCS superconductors. It is established that about 60% of λ is contributed by acoustic phonons in both materials. Using a reasonable value of μ{sup * }= 0.13 for the effective Coulomb repulsion parameter, the superconducting critical temperature T{sub c} is found to be 3.81 K for YC{sub 2} and 2.44 K for LaC{sub 2}, in good agreement with values reported from experimental measurements.
Authors:
 [1] ;  [2] ;  [3]
  1. Sakarya Üniversitesi, Fen-Edebiyat Fakültesi, Fizik Bölümü, 54187 Adapazarı (Turkey)
  2. (BIMAYAM), 54187 Adapazarı (Turkey)
  3. School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL (United Kingdom)
Publication Date:
OSTI Identifier:
22402864
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 15; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COULOMB FIELD; CRITICAL TEMPERATURE; DENSITY FUNCTIONAL METHOD; DENSITY OF STATES; DISPERSION RELATIONS; ELECTRON-PHONON COUPLING; ENERGY SPECTRA; LANTHANUM CARBIDES; PHONONS; POTENTIALS; SPECTRAL FUNCTIONS; SUPERCONDUCTIVITY; SUPERCONDUCTORS