The low-temperature thermal properties of amorphous arsenic

Jones, D. P.; Thomas, Neil; Phillips, W. A.

doi:10.1080/13642817808245329

Cited by 100 publications

(32 citation statements)

References 28 publications

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“…If such uniformity in the magnitude of h indeed exists generally for clathrate hydrates, then it may correspond to a similar uniformity which is known to pertain for glasses (12) and other glasslike solids (15).…”

Section: Discussionmentioning

confidence: 99%

“…We shall be concerned with discussing mainly the temperature and pressure (volume) dependences of h. h(T) for phases or, or', or P is similar to that for a glass (12) or for a glass-like solid (15). An obvious assumption is that this behaviour arises from structural disorder, at least for phase or which is known to be a structure I1 clathrate hydrate.…”

Section: Discussionmentioning

confidence: 99%

“…In particular, for the thermal conductivity, a plateau at about 10 K is found to be superposed on a general increase of h with T. This and other features of the thermal properties are generally considered to be associated with the existence of low-energy, localized excitations, but detailed theoretical interpretation of the plateau is still controversial (12)(13)(14).…”

Section: Thermal Properties Of Nonmetallic Crystals Andmentioning

confidence: 99%

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Clathrate and other solid phases in the tetrahydrofuran–water system: thermal conductivity and heat capacity under pressure

Ross¹,

Andersson²

1982

Can. J. Chem.

108

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RUSSELL G. Ross and PER ANDERSSON. Can. J. Chem. 60,881 (1982). Solid phases in the tetrahydrofuran-water (THF-H20) system were investigated in the temperature range 100-260K and at pressures up to 1.5 GPa. Thermal conductivity, h, and heat capacity per unit volume, pc,, were measured, using the transient hot-wire method. We made measurements on solid phases having nominal compositions THF.17H20, THF,7.1H20, and THF.4.6H20, which we refer to as phases a , P, and y , respectively. Phase a is known to be a structure I1 clathrate hydrate, and h for this phase was found to be similarto other crystalline solids which areglass-like in relation to their thermal properties. Low-energy excitations are known to be relevant to the properties of glass-like solids, and, in the case of phase a , were probably rotational vibrations of the THF guest molecules. Phase was similar, and we inferred that it was probably a structure I clathrate hydrate. Phase y behaved nearly like a normal crystal phase at low temperatures, but h became almost independent of temperature near melting. At 1.1 GPa and 130 K, we found evidence that phase a transformed, on pressurization, to a metastable modification which may be a new high-density form of clathrate hydrate. The astrophysical implications of our results were mentioned briefly. RUSSELL G. ROSS et PER ANDERSSON. Can. J. Chem. 60, 881 (1982). On a ttudie les phases solides dans le systkme tetrahydrofuranne-eau (THF-H20) dans un intewalle de temperature allant de 100 a 260 K et des pressions allant jusqu'a 1,s GPa. On a mesure la conductivite thermique, h, et la capaciti calorifique par unite de volume, pc,, en utilisant la methode du fil chaud transitoire. Nous avons effectue ces mesures sur des phases solides ayant des compositions nominales de THF.17H20, THF.7,1H20 et THF4,6H20 que nous disignons respectivement comme phases a,p et y.On sait que la phase a a une structure I1 d'hydrate de clathrate et on a trouvt que, pour cette phase, h est semblable a celui d'autres solides cristallins qui ressemblent des verres si I'on tient compte de leurs proprietes thermiques. On sait que les excitations de faible energie sont relikes aux proprietes des solides ressemblant a des verres et, dans le cas de la phase a, ce sont probablement des vibrations-rotations des molecules-h8tes de THF. La phase P est semblable et nous en diduisons qu'elle a probablement une structure I d'hydrate de clathrate. La phase y se comporte presque comme une phase cristalline normale a basse temperature, mais h devient presqu'indtpendant de la temperature au voisinage du point de fusion. A 1,l GPa et 130 K, nous avons trouve des indications a l'effet que la phase a se transforme, sous pression, en une forme metastable qui peut &tre une nouvelle forme d'hydrate de clathrate a haute densite. Nous mentionnons brikvement les implications astrophysiques de nos resultats.[Traduit par le journal]

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Thermal Properties Of Nonmetallic Crystals Andmentioning

confidence: 99%

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Clathrate and other solid phases in the tetrahydrofuran–water system: thermal conductivity and heat capacity under pressure

Ross¹,

Andersson²

1982

Can. J. Chem.

108

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“…The scattering of phonons in this frequency region is of importance in the temperature region of the heat-conductivity plateau, universally encountered in amorphous solids. Many explanations have been suggested in order to explain this remarkable plateau, for example Rayleigh scattering from either density or force-constant fluctuations, 2 that might eventually lead to phonon localization, 3,4 phonon-phonon scattering, 5 and scattering of phonons by soft modes. 6 In order to check the validity of these partly conflicting models, and to better understand the anomalous thermal conductivity in these materials, it is relevant to examine the transport of nonequilibrium terahertz phonons in amorphous materials.…”

Section: Introductionmentioning

confidence: 99%

Transport of 29cm−1phonons in hydrogenated amorphous silicon

1996

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The scattering of 29 cm Ϫ1 phonons in hydrogenated amorphous silicon ͑a-Si:H͒ at 2 K is investigated by means of optically generated heat pulses and the ruby phonon detector. The transport is shown to be governed by elastic spatial diffusion and a diffusion coefficient of ϳ1 cm 2 /s. Resonant scattering by soft oscillators, as well as Rayleigh scattering by microvoids or by the disordered network itself account for the experimental findings. In optically excited a-Si:H, the transmission of 29 cm Ϫ1 phonons is reduced by inelastic scattering, proportional to the optical excitation density in a-Si:H and recovers on a 40-ns time scale. These results are discussed in terms of interaction of 29 cm Ϫ1 phonons with optically generated long-lived very high-frequency phonons in a-Si:H. ͓S0163-1829͑96͒00541-3͔

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“…Many inelastic x-ray scattering (IXS) experiments [21][22][23][24][25][26] have shown that the sound attenuation Γ of glasses at frequencies ν close to but smaller than that of the BP is dominated by an "elastic" scattering process, which grows as the fourth power of the frequency. The origin of the strong scattering regime, Γ ∼ ν 4 , is debated in the literature [9,[27][28][29][30][31][32], but recent experiments [3] and theories [33] support the interpretation, dating back to Rayleigh [34], of sound wave scattering from elastic modulus fluctuations. All of the IXS experiments performed up to now have, to the best of our knowledge, supported the idea that the sound damping at these frequencies is not affected by anharmonic processes [35].…”

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confidence: 99%

Anharmonic Damping of Terahertz Acoustic Waves in a Network Glass and Its Effect on the Density of Vibrational States

Baldi¹,

Giordano

Ruta

et al. 2014

Phys. Rev. Lett.

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We report the observation, by means of high-resolution inelastic x-ray scattering, of an unusually large temperature dependence of the sound attenuation of a network glass at terahertz frequency, an unprecedentedly observed phenomenon. The anharmonicity can be ascribed to the interaction between the propagating acoustic wave and the bath of thermal vibrations. At low temperatures the sound attenuation follows a Rayleigh-Gans scattering law. As the temperature is increased the anharmonic process sets in, resulting in an almost quadratic frequency dependence of the damping in the entire frequency range. We show that the temperature variation of the sound damping accounts quantitatively for the temperature dependence of the density of vibrational states. DOI: 10.1103/PhysRevLett.112.125502 PACS numbers: 63.50.Lm, 62.30.+d, 62.65.+k, 66.70.Hk When the wavelength of a sound wave is sufficiently large with respect to the average size of the elastic modulus fluctuations, an amorphous solid behaves in a way similar to a continuous elastic medium. Since the elasticity of a glass is typically correlated on the nanometer scale [1][2][3], the wave propagation is influenced by the heterogeneous elasticity of the material when the frequency reaches the terahertz range [3]. A proper understanding of the propagation of elastic waves in random media is of great interest for many diverse fields. Examples are the attenuation of seismic waves in Earth's lithosphere [4,5] or the ability to tune the thermal conductivity of a thermoelectric material [6,7]. From a more fundamental perspective, the main unsolved problem concerns the nature of the vibrational modes of glasses in the few terahertz frequency range and the associated thermal transport properties [8][9][10]. The reduced density of vibrational states (RDOS) gðωÞ=ω 2 deviates from the Debye prediction and presents a peak, usually termed the boson peak (BP). This excess of states is often related to the known low temperature anomalies of the specific heat and of the thermal conductivity [8].Various models have been proposed to explain the BP anomaly, models that we can classify in three main groups, without the claim of being exhaustive. A first group includes those models, such as the soft potential model [11,12] and the jamming scenario [13], that associate the BP to quasilocalized soft modes. A second class of models relates the excess of states to the elastic heterogeneities of the glass. For instance, Ref. [14] suggests the appearance of localized modes close to the elastic heterogeneities, while the model of Refs. [15,16], recently extended to also take into account the role of anharmonic interactions [17], demonstrates that a distribution of random elastic constants can give rise to a peak in the RDOS. As a third class we mention those models where the BP is explained as a broadened first van Hove singularity, shifted to lower frequency by the disorder [18] and by the difference in mass density between the glass and the corresponding crystalline structure [19,20].The...

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The low-temperature thermal properties of amorphous arsenic

Cited by 100 publications

References 28 publications

Clathrate and other solid phases in the tetrahydrofuran–water system: thermal conductivity and heat capacity under pressure

Clathrate and other solid phases in the tetrahydrofuran–water system: thermal conductivity and heat capacity under pressure

Transport of 29cm−1phonons in hydrogenated amorphous silicon

Anharmonic Damping of Terahertz Acoustic Waves in a Network Glass and Its Effect on the Density of Vibrational States

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