Eur. Phys. J. B 46, 363-366 (2005)
https://doi.org/10.1140/epjb/e2005-00265-5

Optical investigations of the clathrate α-Eu₈Ga₁₆Ge₃₀

¹ Max-Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
² Department of Structural Molecular Science, The Graduate University for Advanced Studies, Okazaki 444-8585, Japan
³ UVSOR Facility, Institute for Molecular Science, Okazaki 444-8585, Japan

Corresponding author: ^a sichelschmidt@cpfs.mpg.de

Received: 4 February 2005
Revised: 7 June 2005
Published online: 18 August 2005

Abstract

We performed measurements of the optical reflectivity in the energy range 0.007–30 eV on the clathrate-VIII type compound α-Eu₈Ga_16-xGe_30x in order to investigate its electronic band structure. The very low charge carrier concentration as well as ferromagnetic ordering of the divalent Eu ions below 10.5 K characterize the spectra at photon energies below ~0.4 eV in accordance with the results of band structure calculations. Disorder induced bound states have been identified to affect the optical conductivity at energies between 10 and 100 meV.