6533b7d8fe1ef96bd1269b4c
RESEARCH PRODUCT
Theory of vibrational anomalies in glasses
Giancarlo RuoccoWalter SchirmacherWalter SchirmacherTullio Scopignosubject
PhysicsGaussianCondensed Matter Physics; ceramics and composites; electronic optical and magnetic materials; Materials Chemistry; metals and alloysEquations of motionVibrational spectrumCondensed Matter PhysicsDebye frequencyElectronic Optical and Magnetic Materialssymbols.namesakeQuantum mechanicsMaterials ChemistryCeramics and CompositessymbolsBoson peakElasticity (economics)Born approximationElastic modulusdescription
Abstract The theory of elasticity with spatially fluctuating elastic constants (heterogeneous-elasticity theory) is reviewed. It is shown that the vibrational anomalies associated with the boson peak can be qualitatively and quantitatively explained in terms of this theory. Two versions of a mean-field theory for solving the stochastic equation of motion are presented: the coherent-potential approximation (CPA) and the self-consistent Born approximation (SCBA). It is shown that the latter is included in the former in the Gaussian and weak-disorder limit. We are able to discuss and explain cases in which the change of the vibrational spectrum by varying an external parameter can be accounted for by changing the Debye frequency (elastic transformation) and cases in which this is not possible. In the latter case a change in the distribution of the elastic moduli has occurred.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2015-01-01 |