Electronic band structure and the X-ray photoemission spectrum of UCu₅In

Abstract

The family of compounds UCu₅M (M ≡ Al, In or Sn) is characterized by the coexistence of magnetic order (antiferromagnetic for M ≡ Al and In; ferri-magnetic for M ≡ Sn) and Kondo lattice effects, by moderate electronic specific heat enhancement (γ/γ₀ ≈ 8 for Al; γ/γ₀ ≈ 11 for both In and Sn) and possibly a mixed-valence ground state. The electronic band structure was calculated by the tight-binding linear muffin-tin orbital method in the atomic sphere approximation. The electronic structure of UCu₅In not unexpectedly shows marked similarities to the electronic structure of the other compounds of the family. The valence band, having a width of about 6eV, is due to prevalent contributions from the Cu 3d and U 5f electrons; the peak from the 5f electrons is situated just above the Fermi level. The X-ray photoemission spectra were taken in vacuum of 5 × 10⁻¹⁰ Torr from the sample surface prepared in situ. Satisfactory agreement between the measured spectrum and that obtained from the calculated electronic structure has been achieved.