Thermal conductivity of disordered harmonic solids

Allen, Philip B.; Feldman, Joseph L.

doi:10.1103/physrevb.48.12581

Cited by 571 publications

(560 citation statements)

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“…As suggested by Zaitsev and Fedorov 39 , optical phonons in HMS and other complex crystals behave as those in an amorphous material. More specifically, scattering in the low-k complex materials is expected to be intense so that the wave vector is no longer a well-defined parameter for vibrations with frequencies above a certain threshold known as the Ioffe-Regel crossover 40,41 . Only extended modes below the crossover behave as propagating phonons.…”

Section: Resultsmentioning

confidence: 99%

“…Only extended modes below the crossover behave as propagating phonons. In comparison, non-extended modes above the crossover can be neither propagating nor localized, and are referred to as diffusons according to the Allen-Feldman theoretical framework 40 , which suggests the occurrence of diffuson behaviour not only in glasses but also in both strongly disordered, crystalline solid solutions and weakly disordered crystals with very complicated unit cells. As HMS is a weakly disordered crystal with complex unit cells, we treat the nonextended vibrational modes as diffusons.…”

Section: Resultsmentioning

confidence: 99%

“…As HMS is a weakly disordered crystal with complex unit cells, we treat the nonextended vibrational modes as diffusons. This simple model has not taken into account strongly localized modes, which transport heat only via hopping caused by anharmonic coupling with extended modes 40,42 . Hence, the lattice thermal conductivity of HMS is expressed as sums of separate contributions from the phonon gas and diffusons,…”

Section: Resultsmentioning

confidence: 99%

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Twisting phonons in complex crystals with quasi-one-dimensional substructures

et al. 2015

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A variety of crystals contain quasi-one-dimensional substructures, which yield distinctive electronic, spintronic, optical and thermoelectric properties. There is a lack of understanding of the lattice dynamics that influences the properties of such complex crystals. Here we employ inelastic neutron scatting measurements and density functional theory calculations to show that numerous low-energy optical vibrational modes exist in higher manganese silicides, an example of such crystals. These optical modes, including unusually low-frequency twisting motions of the Si ladders inside the Mn chimneys, provide a large phase space for scattering acoustic phonons. A hybrid phonon and diffuson model is proposed to explain the low and anisotropic thermal conductivity of higher manganese silicides and to evaluate nanostructuring as an approach to further suppress the thermal conductivity and enhance the thermoelectric energy conversion efficiency. This discovery offers new insights into the structure-property relationships of a broad class of materials with quasi-one-dimensional substructures for various applications.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Twisting phonons in complex crystals with quasi-one-dimensional substructures

et al. 2015

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“…Their contribution to energy transport can be quantified by the energy diffusivity, defined as follows [37,38]. Consider a wavepacket narrowly peaked at frequency ω and localized at r. This wavepacket spreads out in time, such that the square of the width of the wavepacket at time t, divided by t, is independent of t at large t; this constant defines the diffusivity, d(ω).…”

Section: Diffusivity Quasilocalized Modes and Anharmonicity Diffusivitymentioning

confidence: 99%

The jamming scenario—an introduction and outlook

Liu

Nagel

Saarloos

et al. 2011

Dynamical Heterogeneities in Glasses, Colloids, and Granular Media

119

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Abstract. The jamming scenario of disordered media, formulated about 10 years ago, has in recent years been advanced by analyzing model systems of granular media. This has led to various new concepts that are increasingly being explored in in a variety of systems. This chapter contains an introductory review of these recent developments and provides an outlook on their applicability to different physical systems and on future directions. The first part of the paper is devoted to an overview of the findings for model systems of frictionless spheres, focussing on the excess of low-frequency modes as the jamming point is approached. Particular attention is paid to a discussion of the cross-over frequency and length scales that govern this approach. We then discuss the effects of particle asphericity and static friction, the applicability to bubble models for wet foams in which the friction is dynamic, the dynamical arrest in colloids, and the implications for molecular glasses.

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“…Its temperature † Author for correspondence. Email: baldi@science.unitn.it 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 F o r P e e r R e v i e w O n l y dependence is one of the main open problems in the physics of structural glasses, in spite of the great amount of work on the subject (see, for example, [7] and [8]). …”

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confidence: 99%