A universal T2 behavior of low temperature thermal conductivity of some simple molecular polycrystals

Romanova, T. V.; Stachowiak, P.; Jeżowski, A.; Кривчиков, А. И.; Vdovychenko, G.A.

doi:10.1016/j.physb.2014.11.098

Cited by 4 publications

(2 citation statements)

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“…A phenomenological analysis of the thermal conductivity for the monoclinic phase κ m ( T ) can be carried out using two competing terms which account for propagation of acoustic phonons with long relaxation times τ R (ω, T ), i.e., with mean free path larger than the lattice parameters, and for short-wavelength acoustic phonons with the minimum value of τ MIN = π/ω. − Both contributions give rise to the bell-like shape for κ( T ) in a double-log scale. Such a common maximum for a dielectric crystal features the change from an increase of the density of high-energy phonons at low-temperature to a rapid increase of intensity of three-phonon scatterings by the so-called Umklapp processes which strongly limit the thermal conductivity of the crystal. , The κ ph ( T ) or Debye term is written as where x = ℏω/ k B T, Θ D is the Debye temperature, τ R ( x ) is an effective relaxation time for phonon scattering, and c s is a sound velocity averaged over longitudinal and transverse polarizations. Values of Θ D and c s are obtained from the Debye behavior of heat capacity at low temperature.…”

Section: Discussionmentioning

confidence: 99%

“…32,33 The κ ph (T ) or Debye term is written as 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 temperature. The contributions of the dierent phonon-scattering processes are introduced into the relaxation time τ R (x) by means of the Mattiessen's rule,…”

Section: Acs Paragon Plus Environmentmentioning

confidence: 99%

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Glassy Dynamics versus Thermodynamics: The Case of 2-Adamantanone

Szewczyk¹,

Jeżowski²,

Vdovichenko

et al. 2015

J. Phys. Chem. B

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The heat capacity and thermal conductivity of the monoclinic and the fully ordered orthorhombic phases of 2-adamantanone (C10H14O) have been measured for temperatures between 2 and 150 K. The heat capacities for both phases are shown to be strikingly close regardless of the site disorder present in the monoclinic crystal which arises from the occupancy of three nonequivalent sites for the oxygen atom. The heat capacity curves are also well accounted for by an evaluation carried out within the harmonic approximation in terms of the g(ω) vibrational frequency distributions measured by means of inelastic neutron scattering. Such spectral functions show however a significant excess of low frequency modes for the crystal showing statistical disorder. In contrast, large differences are found for the thermal conductivity which contrary to what could be expected, shows the substitutionally disordered crystal to exhibit better heat transport properties than the fully ordered orthorhombic phase. Such an anomalous behavior is understood from examination of the crystalline structure of the orthorhombic phase which leads to very strong scattering of heat-carrying phonons due to grain boundary effects able to yield a largely reduced value of the conductivity as well as to a plateau-like feature at intermediate temperatures which contrasts with a bell-shaped maximum shown by data pertaining the disordered crystal. The relevance of the present findings within the context of glassy dynamics of the orientational glass state is finally discussed.

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Section: Discussionmentioning

confidence: 99%

Section: Acs Paragon Plus Environmentmentioning

confidence: 99%

Glassy Dynamics versus Thermodynamics: The Case of 2-Adamantanone

Szewczyk¹,

Jeżowski²,

Vdovichenko

et al. 2015

J. Phys. Chem. B

Self Cite

View full text Add to dashboard Cite

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Specific features of heat transfer in the orientationally ordered phases of molecular crystals in the region with predominant phonon-phonon scattering

Кривчиков¹,

Romantsova²,

Korolyuk³

et al. 2015

Low Temperature Physics

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Thermal conductivity of an orientationally ordered tert-butanol crystal was measured in the temperature range T = 4–150 K at equilibrium vapor pressure. The literature data on the thermal conductivity of a number of orientationally ordered molecular crystals in the high temperature region were analyzed. It was shown that the thermal conductivity can be described as a sum of two contributions: due to propagating phonons and localized “diffuse” modes. Generally, the contribution of localized “diffuse” modes is inversely proportional to the number of molecules Z in the unit cell and temperature independent. It is suggested that strong hybridization of acoustic phonons and low-frequency optical phonon excitations in ordered crystals is the main factor influencing the heat transfer in a molecular crystal.

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Universal temperature dependence of the thermal conductivity of clathrate compounds, molecular crystals, and glasses at low temperatures

Korolyuk

Кривчиков

Romantsova

2020

Low Temperature Physics

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A new approach is used to analyze the experimental data on the temperature dependence of low-temperature thermal conductivity κ(T) of some typical disordered complex crystals: clathrate hydrates (tetrahydrofuran, methane, xenon), Sr8Ga16Ge30 and p-type Ba8Ga16Ge30 clathrate compounds, YSZ ceramics, molecular structural glasses of 1-propanol, glycerol and D-ethanol exhibiting glass-like behavior of κ(T), and some representatives of regular complex crystals: tetrahydrofuran clathrate hydrate, n-type Ba8Ga16Ge30 clathrate compound, CsDy(MoO4)2 layered crystal, 1-propanol, and D-ethanol. A universal approach to normalizing low-temperature thermal conductivity is proposed, based on the theoretical model of hybridized Klinger–Kosevich excitations. The low-temperature universal behavior of the thermal conductivity of both crystalline and amorphous solids is shown to be a result of the same phenomenon: the hybridization of acoustic and low-lying optical branches.

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A universal T2 behavior of low temperature thermal conductivity of some simple molecular polycrystals

Cited by 4 publications

References 46 publications

Glassy Dynamics versus Thermodynamics: The Case of 2-Adamantanone

Glassy Dynamics versus Thermodynamics: The Case of 2-Adamantanone

Specific features of heat transfer in the orientationally ordered phases of molecular crystals in the region with predominant phonon-phonon scattering

Universal temperature dependence of the thermal conductivity of clathrate compounds, molecular crystals, and glasses at low temperatures

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