Phonon transport and vibrational excitations in amorphous solids
Hideyuki Mizuno,Atsushi Ikeda +1 more
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TLDR
In this paper, a model amorphous solid with a mixture of phonon modes and soft localized modes and disordered and extended modes in the boson peak regime was investigated.Abstract:
One of the long-standing issues concerning the thermal properties of amorphous solids is the complex pattern of phonon transport. Recent advances in experiments and computer simulations have indicated a crossover from Rayleigh scattering to ${\mathrm{\ensuremath{\Omega}}}^{2}$ law (where $\mathrm{\ensuremath{\Omega}}$ is the propagation frequency). A number of theories have been proposed, yet critical tests are missing and the validity of these theories is unclear. In particular, the precise location of the crossover frequency remains controversial, and more critically, even the validity of the Rayleigh scattering has been seriously questioned. To settle these issues, we focus on a model amorphous solid, whose vibrational eigenmodes were recently clarified over a wide frequency regime: a mixture of phonon modes and soft localized modes in the continuum limit and disordered and extended modes in the boson peak regime. The present work demonstrates that Rayleigh scattering occurs in the continuum limit and ${\mathrm{\ensuremath{\Omega}}}^{2}$ damping occurs in the boson peak regime, and these behaviors are therefore linked to the underlying eigenmodes in the corresponding frequency regimes. Our results unambiguously determine the crossover frequency. Furthermore, we establish characteristic scaling laws of phonon transport near the jamming transition, which are consistent with the prediction of the mean-field theory at higher frequencies but inconsistent in the low-frequency, Rayleigh scattering regime. Our results therefore reveal crucial issues to be solved with regard to the current theory.read more
Citations
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Universal Origin of Boson Peak Vibrational Anomalies in Ordered Crystals and in Amorphous Materials
TL;DR: The theory explains the recent experimental observations of boson peak in perfectly ordered crystals, which cannot be explained based on previous theoretical frameworks, and also explains, for the first time, how the vibrational spectrum changes with the atomic density of the solid, and explains recent experimental observed of this effect.
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Pinching a glass reveals key properties of its soft spots
TL;DR: In this paper, it is shown that the number of quasilocalized nonphononic excitations of a glass follows a Boltzmann-like law in terms of the parent temperature from which the glass is quenched.
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Breakdown of continuum elasticity in amorphous solids
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Wave attenuation in glasses: Rayleigh and generalized-Rayleigh scattering scaling.
TL;DR: The results suggest that macroscopic glasses-and, in particular, glasses generated by conventional laboratory quenches that are known to strongly suppress quasilocalized nonphononic excitations-exhibit Rayleigh scaling at the lowest wavenumbers k and a crossover to generalized-Rayleigh scaled at higher k.
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Sound attenuation in stable glasses.
TL;DR: In this paper, a microscopic analysis of sound damping in model glass formers across a range of experimentally relevant preparation protocols is presented, showing that the wavevector where the quartic scaling begins increases by approximately a factor of three and sound attenuation decreases by over an order of magnitude.
References
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Journal ArticleDOI
Anomalous low-temperature thermal properties of glasses and spin glasses
TL;DR: In this article, a linear specific heat at low temperatures for glass follows naturally from general considerations on the glassy state, and the experimentally observed anomalous low-temperature thermal conductivity is predicted.
Journal ArticleDOI
Thermal Conductivity and Specific Heat of Noncrystalline Solids
R. C. Zeller,Robert O. Pohl +1 more
TL;DR: The thermal conductivity of vitreous Si, Se, and silica-and germania-based glasses has been measured between 0.05 and 100 \ifmmode^\circ\else\text degree\fi{}K, suggesting a Rayleigh-type scattering mechanism as mentioned in this paper.
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Jamming at zero temperature and zero applied stress: the epitome of disorder.
Corey S. O'Hern,Corey S. O'Hern,Leonardo E. Silbert,Leonardo E. Silbert,Andrea J. Liu,Sidney R. Nagel +5 more
TL;DR: The results provide a well-defined meaning for "random close packing" in terms of the fraction of all phase space with inherent structures that jam, and suggest that point J is a point of maximal disorder and may control behavior in its vicinity-perhaps even at the glass transition.
Journal ArticleDOI
Point Defects in Metals
TL;DR: In this article, the fraction of atom sites that are vacant for lead at its melting temperature of 327°C (600 K) is computed. But the fraction is not fixed.