Density of Vibrational States of a Hyperquenched Glass

Monaco, Andrea; Chumakov, A. I.; Yue, Yuanzheng; Monaco, G.; Comez, Lucia; Fioretto, D.; Crichton, Wilson A.; Rüffer, R.

doi:10.1103/physrevlett.96.205502

Cited by 62 publications

(82 citation statements)

References 25 publications

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“…Without exception, available results are all in agreement [3,4,[13][14][15][16][17][18][19][20][21][22]: the BP shifts towards higher frequencies and decreases in intensity when the sample becomes stiffer (increase of elastic constants). Recently, it has been proposed to quantitatively test the role played by the changes in the elastic properties by scaling the BP data with the Debye frequency, a quantity defined by the elastic medium.…”

Section: Introductionsupporting

confidence: 65%

Stress-Induced Modification of the Boson Peak Scaling Behavior

et al. 2013

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The scaling behavior of the so-called boson peak in glass-formers and its relation to the elastic properties of the system remains a source of controversy. Here, the boson peak in a binary reactive mixture is measured by Raman scattering (i) on cooling the unreacted mixture well below its glass transition temperature and (ii) after quenching to very low temperature the mixture at different times during isothermal polymerization. These different paths to the glassy phase are able to generate glasses with different amounts of residual stresses, as evidenced by the departure of the elastic moduli from a Cauchy-like relationship. We find that the scaling behavior of the boson peak with the properties of the elastic medium -as measured by the Debye frequency -holds for states in which the system is able to release internal stress and breaks down in the presence of residual stresses. These findings provide new insight into the boson peak behavior and are able to reconcile the apparently conflicting results presented in literature.

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Section: Introductionsupporting

confidence: 65%

Stress-Induced Modification of the Boson Peak Scaling Behavior

et al. 2013

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“…In addition, a strong boson peak in C p /T 3 had already been observed by us in (20 million years old) Dominican amber [10], though apparent residual curing or repolymerization, occurring around the glass transition temperature when rejuvenating those amber samples, hindered a reliable quantitative investigation. Although some authors have tried to correlate the boson peak feature in glasses [38], and even in crystals [39], with transformations of the elastic continuum only, such a Debye-scaling rule is not hold quantitatively in our case. The height of the C p /T 3 boson peak in the hyperaged amber has decreased a 22% from the standard rejuvenated glass, whereas a Debye scaling [38] 3 (, D with D being the Debye frequency) would predict only a 7.4% reduction.…”

Section: Discussionmentioning

confidence: 42%

“…Although some authors have tried to correlate the boson peak feature in glasses [38], and even in crystals [39], with transformations of the elastic continuum only, such a Debye-scaling rule is not hold quantitatively in our case. The height of the C p /T 3 boson peak in the hyperaged amber has decreased a 22% from the standard rejuvenated glass, whereas a Debye scaling [38] 3 (, D with D being the Debye frequency) would predict only a 7.4% reduction. Unfortunately, a similar discussion on the boson peak in ultrastable glasses of indomethacin is not possible since this feature is hardly seen in the specific-heat curves of this glass.…”

Section: Discussionmentioning

confidence: 42%

Do tunneling states and boson peak persist or disappear in extremely stabilized glasses?

Ramos

Pérez-Castañeda

Riobóo

et al. 2015

Low Temperature Physics

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We review and concurrently discuss two recent works conducted by us, which apparently give opposite results. Specifically, we have investigated how extreme thermal histories in glasses can affect their universal properties at low temperatures, by studying: (i) amber, the fossilized natural resin, which is a glass which has experienced a hyperaging process for about one hundred million years; and (ii) ultrastable thin-film glasses of indomethacin. Specific heat C p measurements in the temperature range 0.07 K < T < 30 K showed that the amount of two-level systems, assessed from the linear term at the lowest temperatures, was exactly the same for the pristine hyperaged amber glass as for the subsequently rejuvenated samples, whereas just a modest increase of the boson-peak height (in C p /T 3 ) with increasing rejuvenation was observed, related to a corresponding increase of the Debye coefficient. On the other hand, we have observed an unexpected suppression of the two-level systems in the ultrastable glass of indomethacin, whereas conventionally prepared thin films of the same material exhibit the usual linear term in the specific heat below 1 K ascribed to these universal two-level systems in glasses. By comparing both highly-stable kinds of glass, we conclude that the disappearance of the tunneling two-level systems in ultrastable thin films of indomethacin may be due to the quasi-2D and anisotropic behavior of this glass, what could support the idea of a phonon-mediated interaction between two-level systems.PACS: 65.60.+a Thermal properties of amorphous solids and glasses: heat capacity, thermal expansion, etc.; 64.70.P-Glass transitions of specific systems; 63.50.Lm Glasses and amorphous solids; 81.40.Cd Solid solution hardening, precipitation hardening, and dispersion hardening; aging.

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“…8,9 Experimentally the BP has been studied as a function of macroscopic parameters such as the temperature, 10,11 the density, [12][13][14][15] and the pressure 16,17 or during chemical vitrification 18 or as a function of the quenching rate. 19 It is observed that the BP shifts to higher frequencies and decreases in intensity when the pressure or the density is increased. However, controversial results have been reported on the connection between the BP modification and the change in the elastic medium properties.…”

Section: Introductionmentioning

confidence: 99%

“…However, controversial results have been reported on the connection between the BP modification and the change in the elastic medium properties. In some systems, 14,18,19 it appears that the BP variation is solely associated with the change in the Debye frequency, which accounts for the modifications of the elastic continuum medium. In other cases, 13,[15][16][17] the BP shifts more strongly than suggested by the simple variation of the macroscopic medium.…”

Section: Introductionmentioning

confidence: 99%

Elastic anomalies at terahertz frequencies and excess density of vibrational states in silica glass

2011

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We study the temperature dependence of acousticlike excitations measured by means of inelastic x-ray scattering at terahertz frequencies in silica glass. The apparent sound velocity shows, between 300 and 1600 K, the same temperature variation measured, at lower frequencies, by Brillouin light scattering. On the contrary the vibrations at the boson peak (BP) present a much stronger temperature dependence, as indicated by neutron scattering data. The measured dispersion and damping are used to compute the contribution to the vibrational density of states (VDOS) coming from the propagating acousticlike modes. This part of the VDOS accounts only for a fraction of the BP intensity, indicating that other kinds of excitation accumulate in this frequency range. It is consequently not surprising that the BP does not follow the temperature evolution of the Debye frequency, which describes the modification of the continuum medium. Finally we present a comparison between the experimentally accessible quantities and a recently proposed model for the vibrations in glasses, based on the assumption of random spatial variations of the shear modulus [Schirmacher, Europhys. Lett. 73, 892 (2006)].

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Density of Vibrational States of a Hyperquenched Glass

Cited by 62 publications

References 25 publications

Stress-Induced Modification of the Boson Peak Scaling Behavior

Stress-Induced Modification of the Boson Peak Scaling Behavior

Do tunneling states and boson peak persist or disappear in extremely stabilized glasses?

Elastic anomalies at terahertz frequencies and excess density of vibrational states in silica glass

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