Phonon transport in nanocomposites

Singh, Mahi R.; Guo, Jiaohan; Gumbs, Godfrey

doi:10.1002/pssb.201700142

Cited by 9 publications

(10 citation statements)

References 27 publications

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“…Let us consider that the frequency of propagating phonons in the nanomaterial is

{normalω}_{normalk} .

Hence the dispersion relation for phonons in the nanoparticle and host material are found as:

\begin{array}{c} center & ω_{k} = \frac{v_{0}}{η_{a}} k_{a} \\ center & ω_{k} = \frac{v_{0}}{η_{b}} k_{b} \end{array}

where k a and k b are wave vectors of phonons in the nanoparticle and the host material, respectively.…”

Section: Phonon Dispersion Relationmentioning

confidence: 99%

“…There is considerable interest in understanding heat transport in nanomaterials . Nanomaterials with high thermal conductivity can be used to fabricate temperature‐dependent nanodevices.…”

Section: Introductionmentioning

confidence: 99%

“…It is known that thermal properties such as the specific heat and the thermal conductivity of nanomaterials differ significantly from bulk materials due to the sizes and shapes of the embedding particles . Strong interfacial interactions between the dispersed fillers and matrix lead to enhanced thermal properties.…”

Section: Introductionmentioning

confidence: 99%

“…Recently Singh et al have developed a theory of the phonon dispersion relation for nanomaterials which are made of nanoparticles doped in a host material. They used transfer matrix method by including the size of nanoparticles and the spacing between nanoparticles.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, our theory is valid for nanomaterials and microcomposites. The phonon dispersion relation from Singh et al has been modified in the long‐range approximation. We found very useful properties of these metamaterials.…”

Section: Introductionmentioning

confidence: 99%

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Phonon Conductivity of Nanoparticles Embedded in Dielectric Material

Singh

Guo

Cid

et al. 2018

Physica Status Solidi (b)

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A theory of the thermal conductivity has been developed for nanomaterials made by embedding nanoparticles in a host dielectric material. The phonon dispersion relation has been calculated using the transfer matrix method in the long-range approximation, where the phonon wavelength is larger than the size of the nanoparticle. We found that these nanomaterials have two phonon branches known as ω þ k -phonon and ω À k -phonon branches. For both phonon branches, the density of states and the phonon velocity are calculated. The thermal conductivity is evaluated with the Kubo formalism and the Green's function method for both ω þ k -phonon and ω À k -phonon branches. It is also found that the density of states, phonon velocity and thermal conductivity for both phonon branches depend on the size of the nanoparticles, spacing between nanoparticles, and the phonon refractive index of the nanoparticles and the host material. In the long wave approximation, expressions of the phonon conductivity, the density of states and the phonon velocity have very simple forms which can be used by experimentalists to explain their experiments or plan new experiments. We have also applied our theory to explain the experimental thermal conductivity data of silica-resin, alumina-resin, AlN-resin and CaO-polyethylene nanomaterials. A good agreement between theory and experiments is achieved. Our results furthermore illustrate that one can fabricate new types of nanomaterials with high and low thermal conductivity by adjusting the refractive index contrast between nanoparticles and the host material. These are very novel and interesting properties and they can be used to fabricate new types of thermal devices.

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“…Let us consider that the frequency of propagating phonons in the nanomaterial is