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Layer-dependent Debye temperature and thermal expansion of Ru(0001) by means of high-energy resolution core-level photoelectron spectroscopy
- Source :
- 82 (2010): 195420., info:cnr-pdr/source/autori:Ferrari, Eugenio; Galli, Lorenzo; Miniussi, Elisa; Morri, Maurizio; Panighel, Mirko; Ricci, Maria; Lacovig, Paolo; Lizzit, Silvano; Baraldi, Alessandro/titolo:Layer-dependent Debye temperature and thermal expansion of Ru(0001) by means of high-energy resolution core-level photoelectron spectroscopy/doi:/rivista:/anno:2010/pagina_da:195420/pagina_a:/intervallo_pagine:195420/volume:82
- Publication Year :
- 2010
- Publisher :
- American Physical Society (APS), 2010.
-
Abstract
- The layer-dependent Debye temperature of Ru(0001) is determined by means of high-energy resolution core-level photoelectron spectroscopy measurements. The possibility to disentangle three different components in the Ru 3d{sub 5/2} spectrum of Ru(0001), originating from bulk, first-, and second-layer atoms, allowed us to follow the temperature evolution of their photoemission line shapes and binding energies. Temperature effects were detected, namely, a lattice thermal expansion and a layer-dependent phonon broadening, which was interpreted within the framework of the Hedin-Rosengren formalism based on the Debye theory. The resulting Debye temperature of the top-layer atoms is 295{+-}10 K, lower than that of the bulk (T=668{+-}5 K) and second-layer (T=445{+-}10 K) atoms. While these results are in agreement with the expected phonon softening at the surface, we show that a purely harmonic description of the motion of the surface atoms is not valid, since anharmonic effects contribute significantly to the position and line shape of the different core-level components.
- Subjects :
- Materials science
Phonon
Binding energy
Anharmonicity
Atmospheric temperature range
Condensed Matter Physics
Debye temperature
ruthenium
core level spectroscopy
thermal expansion
Electron spectroscopy
Spectral line
Electronic, Optical and Magnetic Materials
symbols.namesake
symbols
Atomic physics
Spectroscopy
Debye model
Subjects
Details
- ISSN :
- 1550235X and 10980121
- Volume :
- 82
- Database :
- OpenAIRE
- Journal :
- Physical Review B
- Accession number :
- edsair.doi.dedup.....0f337b49b10a866e452a784190d5de79