Photoemission and Optical Spectroscopy of i-ZnMgEr Quasicrystal
A. Suchodolskisa, W. Assmusb, G.-J. Babonasa, L. Giovanellic, U.O. Karlssond, V. Karpusa, G. Le Laye, A. Rėzaa and E. Uhrigb
aSemiconductor Physics Institute, A. Goštauto 11, 01108 Vilnius, Lithuania
bPhysikalisches Institut, J.W. Goethe-Universität, Robert-Mayer Str. 2-4, 60325 Frankfurt am Main, Germany
cTASC-INFM, S.S. 14 Km 163.5, 34012 Basoviza, Trieste, Italy
dDepartment of Materials Physics, KTH, P.O. Box Electrum 229, 16440 Kista, Sweden
eCRMC2-CNRS, Campus de Luminy, Case 913, 13288 Marseille Cedex 9, France
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Received: 22 08 2004;
The results of photoemission and optical studies of icosahedral single-grain ZnMgEr quasicrystals are presented. Synchrotron radiation photoemission measurements were performed on in situ cleaved samples at 10-10 mbar pressure and low, 140-150 K temperature. The valence band photoemission spectra measured reveal a simple metal-type valence band of icosahedral ZnMgEr with a distinct Fermi edge cut-off and with a sharp pseudogap feature. The photoemission spectra of shallow Mg 2p and Zn 3d core levels indicate a coordination shift of Mg 2p spin--orbit doublet and an oscillating dependence of Zn 3d photoemission line components on the photon energy within the hν=20-160 eV range investigated. The optical response of icosahedral ZnMgEr, a dispersion of the dielectric function, was measured by the spectroscopic ellipsometry technique in the 0.5-5.0 eV spectral range. The optical spectra of the quasicrystal indicate the Drude-type optical response superimposed with a peak of interband optical transitions. The interband optical transitions can be modelled with the pseudogap parameters which agree with those deduced in an analysis of the photoemission valence band spectra.
DOI: 10.12693/APhysPolA.107.412
PACS numbers:71.23.Ft