Layer-dependent Debye temperature and thermal expansion of Ru(0001) by means of high-energy resolution core-level photoelectron spectroscopy

Journal Article · Mon Nov 15 00:00:00 EST 2010 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PHYSREVB.82.195420· OSTI ID:21502887

Ferrari, Eugenio; Galli, Lorenzo; Miniussi, Elisa; Morri, Maurizio; Panighel, Mirko; Ricci, Maria ^[1]; Lacovig, Paolo; Lizzit, Silvano ^[2]; Baraldi, Alessandro ^[1]

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1. Physics Department, University of Trieste, Via Valerio 2, I-34127 Trieste (Italy)
2. Sincrotrone Trieste S.C.p.A., Strada Statale 14 Km 163.5, 34149 Trieste (Italy)

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.

• OSTI ID: 21502887
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Vol. 82, Issue 19; Other Information: DOI: 10.1103/PhysRevB.82.195420; (c) 2010 The American Physical Society; ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ATOMS
BINDING ENERGY
DEBYE TEMPERATURE
ENERGY RESOLUTION
EVOLUTION
LAYERS
PHONONS
PHOTOELECTRON SPECTROSCOPY
PHOTOEMISSION
RUTHENIUM
SPECTRA
SURFACES
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 0400-1000 K
THERMAL EXPANSION
ELECTRON SPECTROSCOPY
ELEMENTS
EMISSION
ENERGY
EXPANSION
METALS
PLATINUM METALS
QUASI PARTICLES
REFRACTORY METALS
RESOLUTION
SECONDARY EMISSION
SPECTROSCOPY
TEMPERATURE RANGE
TRANSITION ELEMENTS