Indication of van Hove singularities in the density of states of ZnMg(Y,Ho) quasicrystals
2003 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 68, no 5Article in journal (Refereed) Published
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.
Place, publisher, year, edition, pages
2003. Vol. 68, no 5
y-mg-zn, electronic-structure, quasicrystals, transport, pseudogap, energy, znmgy, tb
IdentifiersURN: urn:nbn:se:kth:diva-22803DOI: 10.1103/PhysRevB.68.054207ISI: 000185240100045OAI: oai:DiVA.org:kth-22803DiVA: diva2:341501
QC 201005252010-08-102010-08-10Bibliographically approved