The Boson peak and the phonons in glasses
Despite the presence of topological disorder, phonons seem to exist also in glasses at very high frequencies (THz) and they remarkably persist into the supercooled liquid. A universal feature of such a systems is the Boson peak, an excess of states over the standard Debye contribution at the vibrati...
| Autores: | , , , , |
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| Tipo de documento: | artigo |
| Data de publicação: | 2004 |
| País: | España |
| Recursos: | Universidad Complutense de Madrid (UCM) |
| Repositório: | Docta Complutense |
| Idioma: | inglês |
| OAI Identifier: | oai:docta.ucm.es:20.500.14352/52190 |
| Acesso em linha: | https://hdl.handle.net/20.500.14352/52190 |
| Access Level: | Acceso aberto |
| Palavra-chave: | 53 Instantaneous normal-modes Density-of-states Dynamical structure factor Random-matrix theory Supercooled liquids Vibrational excitations Disordered-systems Vitreous silica Relaxation processes Molucular-dynamics. Física-Modelos matemáticos |
| Resumo: | Despite the presence of topological disorder, phonons seem to exist also in glasses at very high frequencies (THz) and they remarkably persist into the supercooled liquid. A universal feature of such a systems is the Boson peak, an excess of states over the standard Debye contribution at the vibrational density of states. Exploiting the euclidean random matrix theory of vibrations in amorphous systems, we show that this peak is the signature of a phase transition in the space of the stationary points of the energy, from a minima-dominated phase (with phonons) at low energy to a saddle-point dominated phase (without phonons). The theoretical predictions are checked by means of numeric simulations. |
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