Collective Nature of the Boson Peak and Universal Transboson Dynamics of Glasses

Chumakov, A. I.; Sergueev, I.; Bürck, U. van; Schirmacher, Walter; Asthalter, T.; Rüffer, R.; Leupold, O.; Petry, W.

doi:10.1103/physrevlett.92.245508

Cited by 138 publications

(125 citation statements)

References 37 publications

Supporting

Mentioning

105

Contrasting

Unclassified

Order By: Relevance

“…It is well known that, at least for fragile liquids, the shape of the spectrum changes with temperature. An excess of soft modes with respect to the Debye model for the density of states, the so-called Boson peak [22], shifts toward higher frequencies as the system is cooled [18,24,25]. Those modes presumably contribute significantly to the change of mean square displacement and to the vibrational specific heat [18,19].…”

mentioning

confidence: 99%

Correlations between Vibrational Entropy and Dynamics in Liquids

Wyart

2010

Phys. Rev. Lett.

View full text Add to dashboard Cite

A relation between vibrational entropy and particles mean square displacement is derived in supercooled liquids, assuming that the main effect of temperature changes is to rescale the vibrational spectrum. Deviations from this relation, in particular due to the presence of a Boson peak whose shape and frequency changes with temperature, are estimated. Using observations of the short-time dynamics in liquids of various fragility, it is argued that (i) if the crystal entropy is significantly smaller than the liquid entropy at Tg, the extrapolation of the vibrational entropy leads to the correlation TK ≈ T0, where TK is the Kauzmann temperature and T0 is the temperature extracted from the Vogel-Fulcher fit of the viscosity. (ii) The jump in specific heat associated with vibrational entropy is very small for strong liquids, and increases with fragility. The analysis suggests that these correlations stem from the stiffening of the Boson peak under cooling, underlying the importance of this phenomenon on the dynamical arrest.PACS numbers: 64.70. Pf, When a liquid is cooled sufficiently rapidly to avoid crystallization, the relaxation time τ below which it behaves as a solid increases up to the glass transition temperature T g where the liquid falls out of equilibrium. In strong liquids τ displays an Arrhenius dependence on temperature, but in other liquids, said to be fragile, the slowing-down of the dynamics is much more pronounced. In general the dynamics is well captured by the VogelFulcher law log(τ ) = C + U/(T − T 0 ), although nondiverging functional forms can also reproduce the dynamics well [1]. As the temperature evolves, two quantities appear to be good predictors of τ : the space available for the rattling of the particles on the picosecond time scales [2,3], embodied by the particles mean square displacement u 2 observable in scattering experiments, and the difference between the liquid and the crystal entropy [4]. When extrapolated below T g this quantity vanishes at some T K , the Kauzmann temperature [5], which appears to correspond rather well to the temperature T 0 extracted from the Vogel-Fulcher law [6]. The correlation between dynamics and thermodynamics has been interpreted early on as the signature of a thermodynamical transition at T K toward an ideal glass where the configurational entropy associated with the number of metastable states visited by the dynamics, or inherent structures, would vanish [7]. This view is appealing and still influential today [8,9], although it is not devoid of conceptual problems [10]. Elastic models [11][12][13] propose an alternative scenario of the glass transition: fragile liquids are simply those which stiffen under cooling, reducing the particle mean square displacement and increasing the activation barriers that must be overcome to flow. In this view the rapid change of entropy in fragile liquids stem from the temperature dependence of the high-frequency elastic moduli [14]. This is consistent with some observations supporting that fragile liquids stiffen mor...

show abstract

mentioning

confidence: 99%

Correlations between Vibrational Entropy and Dynamics in Liquids

Wyart

2010

Phys. Rev. Lett.

View full text Add to dashboard Cite

show abstract

“…[13][14][15][16] Figure 8 presents the reduced low-frequency Raman spectra of KMWPO and RbMWPO glasses in two different reduction schemes:…”

Section: E Low-frequency Raman Scattering: Boson Peakmentioning

confidence: 99%

“…The first technique gives information about short-range structure of glasses and allows studying the so-called "Boson peak." [12][13][14][15][16] Study of the Boson peak is of great interest since its origin still remains unclear. [13][14][15][16] On the other hand, heat capacity studies may provide, among others, some information on fragility, structural relaxation, and aging effects in glasses.…”

Section: Introductionmentioning

confidence: 99%

“…[12][13][14][15][16] Study of the Boson peak is of great interest since its origin still remains unclear. [13][14][15][16] On the other hand, heat capacity studies may provide, among others, some information on fragility, structural relaxation, and aging effects in glasses. [17][18][19][20] A particularly suitable technique for studies of glass transitions is modulated differential scanning calorimetry ͑MDSC͒ since it gives information on both real and imaginary parts of heat capacity.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Heat capacity, Raman, and Brillouin scattering studies of M2O–MgO–WO3–P2O5 glasses (M=K,Rb)

Mączka

Hanuza

Baran

et al. 2006

The Journal of Chemical Physics

View full text Add to dashboard Cite

The authors report the results of temperature-dependent Brillouin scattering from both transverse and longitudinal acoustic waves, heat capacity studies as well as room temperature Raman scattering studies on M 2 O-MgO-WO 3 -P 2 O 5 glasses ͑M=K,Rb͒. These results were used to obtain information about structure and various properties of the studied glasses such as fragility, elastic moduli, ratio of photoelastic constants, and elastic anharmonicity. They have found that both glasses have similar properties but replacement of K + ions by Rb + ions in the glass network leads to decrease of elastic parameters and P 44 photoelastic constant due to increase of fragility. Based on Brillouin spectroscopy they show that a linear correlation between longitudinal and shear elastic moduli holds over a large temperature range. This result supports the literature data that the Cauchy-type relation represents a general rule for amorphous solids. An analysis of the Boson peak revealed that the form of the frequency distribution of the excess density of states is in agreement with the Euclidean random matrix theory. The reason of the observed shift of the maximum frequency of the Boson peak when K + ions are substituted for Rb + ions is also briefly discussed.

show abstract

“…This substance has been measured by MS, 44 NFS, 45,46 and nuclear inelastic scattering. 47 However, due to the drastic decrease of the LambMössbauer factor f LM , above T g these measurements hit an upper limit at ϳ210 K for NFS and ϳ212 K for MS where the countrates proportional to f LM 2 and f LM , respectively, become ϳ0. SRPAC, by contrast, is independent of f LM .…”

Section: Methodsmentioning

confidence: 99%

Synchrotron-radiation-based perturbed angular correlations used in the investigation of rotational dynamics in soft matter

et al. 2006

Self Cite

View full text Add to dashboard Cite

A new method, synchrotron-radiation-based perturbed angular correlations, was applied to study rotational dynamics of Mössbauer atoms in soft condensed matter, using incoherent nuclear resonant scattering of synchrotron radiation. A theory was developed that describes the correlations for the scattering by an ensemble of randomly oriented spins under the influence of rotational relaxation. In a feasibility study a molecular glass former doped by probe molecules was investigated above the glass transition up to the normal liquid state. A comparison of the obtained rotational relaxation rates with data from dielectric spectroscopy shows that the probe molecules reproduce the dynamics of the glass former.

show abstract

Collective Nature of the Boson Peak and Universal Transboson Dynamics of Glasses

Cited by 138 publications

References 37 publications

Correlations between Vibrational Entropy and Dynamics in Liquids

Correlations between Vibrational Entropy and Dynamics in Liquids

Heat capacity, Raman, and Brillouin scattering studies of M2O–MgO–WO3–P2O5 glasses (M=K,Rb)

Synchrotron-radiation-based perturbed angular correlations used in the investigation of rotational dynamics in soft matter

Contact Info

Product

Resources

About