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- Suchodolskis, A., et al.
(författare)
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Indication of van Hove singularities in the density of states of ZnMg(Y,Ho) quasicrystals
- 2003
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 68:5
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Tidskriftsartikel (refereegranskat)abstract
- We present a low-temperature synchrotron-radiation photoelectron microspectroscopy study of the valence bands of single-grain icosahedral ZnMgY and ZnMgHo quasicrystals. Their valence band photoemission spectra reveal in both cases a simple metal-type behavior with a clear metallic Fermi edge and a sharp pseudogap feature: the spectral intensity exhibits a maximum at approximate to0.7 eV below the chemical potential and a subsequent decrease as the Fermi level is approached. The analysis of the pseudogap feature, based on the band-structure hypothesis, shows that it corresponds to the van Hove singularities in the density of states (DOS), which originate from the intersections of the isoenergetic surface with the 222100 and 311111 Bragg planes. The reconstructed density of states agrees in general trends with the theoretical first-principles DOS of hexagonal ZnMgY approximants, and correctly reproduces the experimental value of i-ZnMgY electronic specific-heat coefficient.
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| 2. |
- Suchodolskis, A., et al.
(författare)
-
Pseudogap structure in icosahedral ZnMgY and ZnMgHo quasicrystals
- 2003
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Ingår i: Applied Surface Science. - 0169-4332 .- 1873-5584. ; 212, s. 485-490
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Tidskriftsartikel (refereegranskat)abstract
- The results of a photoemission study of icosahedral single-grain ZnMg(Y, Ho) quasicrystals and their crystalline approximant Zn2Mg are presented. Synchrotron radiation photoemission measurements have been performed on in situ cleaved samples at low temperature of approximate to90 K and 10(-10) mbar pressure. The spectra obtained indicate simple metal-type valence bands (VB) with distinct Fermi edge cutoff. Analysis of the Fermi edge spectra reveals the presence of a pseudogap in i-ZnMg(Y, Ho) quasicrystals. The pseudogap corresponds to a rather sharp DOS dip at the Fermi level with th approximate to50% (of the normal DOS) depth and the approximate to0.8 eV width. The values of i-ZnMg(Y, Ho) pseudogap parameters are comparable with those of other quasicrystals.
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