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 |