SURFACE CORE-LEVEL SHIFTS ON GE(100) - C(4X2) TO 2X1 AND 1X1 PHASE-TRANSITIONS
1992 (English)In: Physical Review B Condensed Matter, ISSN 0163-1829, E-ISSN 1095-3795, Vol. 45, no 12, 6692-6699 p.Article in journal (Refereed) Published
By comparing, under identical experimental conditions, high-resolution synchrotron-radiation core-level photoemission spectra taken from both Ge(111) and Ge(100) samples, we establish that the decomposition of the Ge 3d lines from the clean Ge(100) 2 x 1 surface at room temperature requires two surface components shifted by -0.23 and -0.60 eV relative to the bulk one. This deconvolution is fully consistent with the asymmetric-dimer reconstruction model of this surface. We further study the reversible phase transitions that occur on this surface: 2 x 1 <--> c(4 x 2) at low temperature; 2 x 1 <--> 1 x 1 at high temperature. We show from both core-level and valence-band studies that the number of dimer bonds is essentially conserved in these transitions. We also suggest, by comparing a dimer with an Ising spin, that these transitions correspond, respectively, to an antiferromagnetic ordering at low temperatures and to a paramagnetic disordering at high temperatures.
Place, publisher, year, edition, pages
1992. Vol. 45, no 12, 6692-6699 p.
IdentifiersURN: urn:nbn:se:kth:diva-84178DOI: 10.1103/PhysRevB.45.6692ISI: A1992HL04900031OAI: oai:DiVA.org:kth-84178DiVA: diva2:499255
NR 201408052012-02-132012-02-132012-02-13Bibliographically approved