Coupling of localized guest vibrations with the lattice modes in clathrate hydrates

Tse, John S.; Shpakov, V. P.; Belosludov, V. R.; Trouw, F.; Handa, Y. P.; Press, W.

doi:10.1209/epl/i2001-00250-2

Cited by 98 publications

(95 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…It is well known that one way to reduce lattice thermal conductivity (LTC) is to introduce low-frequency lattice vibrations to scatter heat-carrying acoustic phonons (21-24). This has been proven a very effective approach for realizing the extremely low LTC through the randomly fluctuating rattling fillers on the void-sublattice interlocking with the rigid framework in filled skutterudites (23,24) and clathrates (14,25,26). In both systems, all void fillers are individually embedded in a flattened potential energy surface due to the weak bonding or interaction with the framework (12,13,22,23,27,28) and show ultralarge atom displacement parameters (ADPs).…”

Section: Resultsmentioning

confidence: 99%

Part-crystalline part-liquid state and rattling-like thermal damping in materials with chemical-bond hierarchy

Qiu

Wei

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

254

209

View full text Add to dashboard Cite

Understanding thermal and phonon transport in solids has been of great importance in many disciplines such as thermoelectric materials, which usually requires an extremely low lattice thermal conductivity (LTC). By analyzing the finite-temperature structural and vibrational characteristics of typical thermoelectric compounds such as filled skutterudites and Cu 3 SbSe 3 , we demonstrate a concept of part-crystalline part-liquid state in the compounds with chemicalbond hierarchy, in which certain constituent species weakly bond to other part of the crystal. Such a material could intrinsically manifest the coexistence of rigid crystalline sublattices and other fluctuating noncrystalline sublattices with thermally induced largeamplitude vibrations and even flow of the group of species atoms, leading to atomic-level heterogeneity, mixed part-crystalline partliquid structure, and thus rattling-like thermal damping due to the collective soft-mode vibrations similar to the Boson peak in amorphous materials. The observed abnormal LTC close to the amorphous limit in these materials can only be described by an effective approach that approximately treats the rattling-like damping as a "resonant" phonon scattering.sublattice melting | partial Grüneisen parameter | first principles | anharmonicity U nderstanding thermal and phonon transport in solids has been of great importance in many disciplines such as thermoelectrics (1-3), phononic materials (4), and thermal management composites (5). The interplay among chemical bonds, lattice dynamics, and thermal transport in materials is also an attractive topic in condensed matter physics (6) and materials science (7). Thermal transport is a key issue in thermoelectric (TE) energy-conversion materials, which are regarded among the potential candidates for revolutionizing waste-heat recovery (2, 7-9). The dimensionless figure of merit of a TE material is defined as ZT = TS 2 σ=κ, where T, S, σ, and κ are the absolute temperature, Seebeck coefficient, electrical conductivity, and thermal conductivity, respectively. To improve the efficiency of TE conversion, many approaches aim at reducing the thermal conductivity, especially the lattice part, to a minimum level, namely the realization of phonon-glass-like thermal transport (1, 7).TE materials research primarily focuses on solid and crystalline thermoelectrics. It has been long viewed that all solids contain strong interatomic interactions without even an exception, and thus the established approaches to describe thermal transports in crystalline solids, including TE solids, are solely based on the perturbative "small-parameter" approximation to lattice dynamics of atoms around their equilibrium positions, i.e., phonons and phonon-phonon interactions (10, 11). As a result, crystallographic homogeneity at the atomic level in solid materials has overwhelmingly been accepted. However, recent work on exploring novel TE materials went noticeably beyond the conventional knowledge of solid TE compounds being ideally crystalline, atomically...

show abstract

Section: Resultsmentioning

confidence: 99%

Part-crystalline part-liquid state and rattling-like thermal damping in materials with chemical-bond hierarchy

Qiu

Wei

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

254

209

View full text Add to dashboard Cite

show abstract

“…Les modes observés à 7 et 10.5 meV sont attribués aux mouvements de translation de la sous-structure aqueuse [29]. On peut remarquer un épaulement à basse fréquence de la bande à 7 meV du clathrate hydrate de xénon, signature caractéristique de la structure de type I. Les modes en-dessous de 5 meV sont attribués aux molécules encapsulées.…”

Section: Modes Translationnels Des Cagesunclassified

“…Récemment, cette dernière hypothèse a été vérifiée par une série d'analyses expérimentales et théoriques [39]. Des calculs théoriques de dynamique de réseau ont mis en évidence un croisement évité entre les branches acoustiques du clathrate hydrate et les modes « rattling » des molécules incluses [40,41], comme illustré par les courbes de dispersion des phonons du clathrate hydrate de xénon (Figure 8). Ce phénomène est dû au fait que les branches des phonons mis en jeu possèdent les mêmes représentations irréductibles, autrement dit à l'existence d'interactions fortes entre les sous-structures aqueuses et invitées.…”

Section: Conductivité Thermiqueunclassified

“…Ainsi, la molécule de méthane dans les cages d'un hydrate représente un système modèle de molécule non-polaire. Toutefois, le caractère 3-D de ce rotateur rend l'analyse de l'effet tunnel par diffusion inélastique des neutrons [40][41][42][43][44][45][46][47][48] relativement complexe dans le cadre de ce cours. En effet, le clathrate hydrate de méthane cristallise dans une structure de type I dans laquelle les deux types de cages sont remplis.…”

Section: Exemple De L'hydrate De Iodo-méthaneunclassified

See 1 more Smart Citation

Les clathrates hydrates

Desmedt

2010

JDN 16 – Diffusion Inélastique Des Neutrons Pour l'Etude Des Excitations Dans La Matiére Condensée

View full text Add to dashboard Cite

“…metal-Si clathrates [18] and skutterudites [19]. Several hypotheses have been suggested to explain this observation, the most studied being the "resonant scattering" model [16,[20][21][22][23], which originates in hydrates from "avoided-crossings" of lattice acoustic phonons with localised guest vibrations of identical symmetry [21][22][23] dissipating heat transport. Experimental measurements of thermal conductivity in (type I) methane hydrate exhibit a crystal-like temperature dependence below 90 K, with glass-like behaviour above this temperature [24], while similar low-temperature behaviour is observed in some semi-conductor clathrates [25].…”

Section: Introductionmentioning

confidence: 99%

Mechanisms for thermal conduction in hydrogen hydrate

English

Gorman

MacElroy

2012

The Journal of Chemical Physics

View full text Add to dashboard Cite

Extensive equilibrium molecular dynamics (MD) simulations have been performed to investigate thermal conduction mechanisms via the Green-Kubo approach for (type II) hydrogen hydrate, at 0.05 kbar and between 30 and 250 K, for both lightly-filled H 2 hydrates (1s4l) and for more densely-filled H 2 systems (2s4l), in which four H 2 molecules are present in the large cavities, with respective single-and doubleoccupation of the small cages. The TIP4P water model was used in conjunction with a fully atomistic hydrogen potential along with long-range Ewald electrostatics. It was found that substantially less damping in guest-host energy transfer is present in hydrogen hydrate as is observed in common type I clathrates (e.g., methane hydrate), but more akin in to previous results for type II and H methane hydrate polymorphs.This gives rise to larger thermal conductivities relative to common type I hydrates, and also larger than type II and H methane hydrate polymorphs, and a more crystallike temperature dependence of the thermal conductivity. a) Corresponding author.

show abstract

Coupling of localized guest vibrations with the lattice modes in clathrate hydrates

Cited by 98 publications

References 27 publications

Part-crystalline part-liquid state and rattling-like thermal damping in materials with chemical-bond hierarchy

Part-crystalline part-liquid state and rattling-like thermal damping in materials with chemical-bond hierarchy

Les clathrates hydrates

Mechanisms for thermal conduction in hydrogen hydrate

Contact Info

Product

Resources

About