We measured the density of vibrational states (DOS) and the specific heat of various glassy and crystalline polymorphs of SiO <sub>2</sub>. The typical (ambient) glass shows a well-known excess of specific heat relative to the typical crystal (α-quartz). This, however, holds when comparing a lower-density glass to a higher-density crystal. For glassy and crystalline polymorphs with matched densities, the DOS of the glass appears as the smoothed counterpart of the DOS of the corresponding crystal; it reveals the same number of the excess states relative to the Debye model, the same number of all states in the low-energy region, and it provides the same specific heat. This shows that glasses have higher specific heat than crystals not due to disorder, but because the typical glass has lower density than the typical crystal.

We measured the density of vibrational states (DOS) and the specific heat of various glassy and crystalline polymorphs of SiO2. The typical (ambient) glass shows a well-known excess of specific heat relative to the typical crystal (alpha-quartz). This, however, holds when comparing a lower-density glass to a higher-density crystal. For glassy and crystalline polymorphs with matched densities, the DOS of the glass appears as the smoothed counterpart of the DOS of the corresponding crystal; it reveals the same number of the excess states relative to the Debye model, the same number of all states in the low-energy region, and it provides the same specific heat. This shows that glasses have higher specific heat than crystals not due to disorder, but because the typical glass has lower density than the typical crystal.

Role of Disorder in the Thermodynamics and Atomic Dynamics of Glasses / Chumakov, A. I.; Monaco, Giulio; Fontana, Aldo; Bosak, A.; Hermann, R. P.; Bessas, D.; Wehinger, B.; Crichton, W. A.; Krisch, M.; Rüffer, R.; Baldi, Giacomo; Carini J. r., G.; Carini, G.; D’Angelo, G.; Gilioli, E.; Tripodo, G.; Zanatta, Marco; Winkler, B.; Milman, V.; Refson, K.; Dove, M. T.; Dubrovinskaia, N.; Dubrovinsky, L.; Keding, R.; Yue, Y. Z.. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 112:2(2014), pp. 025502.025502-1-025502.025502-6. [10.1103/PhysRevLett.112.025502]

Role of Disorder in the Thermodynamics and Atomic Dynamics of Glasses

Monaco, Giulio;Fontana, Aldo;Baldi, Giacomo;Zanatta, Marco;
2014

Abstract

We measured the density of vibrational states (DOS) and the specific heat of various glassy and crystalline polymorphs of SiO 2. The typical (ambient) glass shows a well-known excess of specific heat relative to the typical crystal (α-quartz). This, however, holds when comparing a lower-density glass to a higher-density crystal. For glassy and crystalline polymorphs with matched densities, the DOS of the glass appears as the smoothed counterpart of the DOS of the corresponding crystal; it reveals the same number of the excess states relative to the Debye model, the same number of all states in the low-energy region, and it provides the same specific heat. This shows that glasses have higher specific heat than crystals not due to disorder, but because the typical glass has lower density than the typical crystal.
2
Chumakov, A. I.; Monaco, Giulio; Fontana, Aldo; Bosak, A.; Hermann, R. P.; Bessas, D.; Wehinger, B.; Crichton, W. A.; Krisch, M.; Rüffer, R.; Baldi, Giacomo; Carini J. r., G.; Carini, G.; D’Angelo, G.; Gilioli, E.; Tripodo, G.; Zanatta, Marco; Winkler, B.; Milman, V.; Refson, K.; Dove, M. T.; Dubrovinskaia, N.; Dubrovinsky, L.; Keding, R.; Yue, Y. Z.
Role of Disorder in the Thermodynamics and Atomic Dynamics of Glasses / Chumakov, A. I.; Monaco, Giulio; Fontana, Aldo; Bosak, A.; Hermann, R. P.; Bessas, D.; Wehinger, B.; Crichton, W. A.; Krisch, M.; Rüffer, R.; Baldi, Giacomo; Carini J. r., G.; Carini, G.; D’Angelo, G.; Gilioli, E.; Tripodo, G.; Zanatta, Marco; Winkler, B.; Milman, V.; Refson, K.; Dove, M. T.; Dubrovinskaia, N.; Dubrovinsky, L.; Keding, R.; Yue, Y. Z.. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 112:2(2014), pp. 025502.025502-1-025502.025502-6. [10.1103/PhysRevLett.112.025502]
File in questo prodotto:
File Dimensione Formato  
PhysRevLett.112.025502.pdf

accesso aperto

Tipologia: Versione editoriale (Publisher’s layout)
Licenza: Tutti i diritti riservati (All rights reserved)
Dimensione 1.17 MB
Formato Adobe PDF
1.17 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11572/173689
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 103
  • ???jsp.display-item.citation.isi??? 101
social impact