2008/06/24 by J. Teyssier, Rolf Lortz, R. Lortz +7 · 49 citations
Materials Science · Physics and Astronomy · #Boride #Boron #Condensed matter physics #Coupling (piping) #Density of states #Electrical resistivity and conductivity #Ion #Iron-based superconductors research #Materials science #Metallurgy #Nuclear physics #Optical conductivity #Phonon #Physics #Quantum mechanics #Rare-earth and actinide compounds #Superconductivity #Superconductivity in MgB2 and Alloys #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.78.134504
published in Physical Review B 78(13) (American Physical Society)
arxiv created 2008/06/24 · openalex publication_date 2008/10/02 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We report a detailed study of specific heat, electrical resistivity, and optical spectroscopy in the superconducting boride LuB12 (Tc=0.4 K), and compare it to the higher Tc compound ZrB12 (Tc=6 K). Both compounds have the same structure based on enclosed metallic Lu or Zr ions in oversized boron cages. The infrared reflectivity and ellipsometry in the visible range allow us to extract the optical conductivity from 6 meV to 4 eV in the normal state from 20 to 280 K. By extracting the superconducting properties, phonon density of states, and electron-phonon coupling function from these measurements, we discuss the important factors governing Tc and explain the difference between the two compounds. The phonon density of states seems to be insignificantly modified by substitution of Zr with Lu. However, the soft vibrations of the metal ions in boron cages, responsible for the relatively high Tc in ZrB12, have almost no contribution to the electron-phonon coupling in LuB12.