Lattice thermal conductivity including phonon frequency shifts and scattering rates induced by quartic anharmonicity in cubic oxide and fluoride perovskites

Controlling thermal conductivity of materials is very important in various applications, such as thermal management and energy conversion. We have been utilizing femtosecond phonon spectroscopy to excite and detect coherent phonons in various materials. However, the impact of coherent phonons to overall heat transport is still unknown. In this paper, we developed a small perturbation model in molecular dynamics (MD) to simulate coherent phonons and investigate the effect on thermal conductivity in bismuth telluride. The phonon frequency and lifetime predicted by our model agree very well with experimental results. It is found that at very low temperature, the lattice thermal conductivity, predicted by quasi-equilibrium Green-Kubo method, can be greatly enhanced upon coherent phonon generation. Our results suggest that it is possible to control lattice thermal conductivity effectively via manipulating coherent phonons.

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Anharmonic phonon frequency and ultralow lattice thermal conductivity in β-Cu2Se liquid-like thermoelectrics

Physical Chemistry Chemical Physics ◽

10.1039/d0cp04591h ◽

2020 ◽

Vol 22 (48) ◽

pp. 28086-28092

Author(s):

Wenjie Zhang ◽

Chong Zheng ◽

Yanbing Dong ◽

Jia-Yue Yang ◽

Linhua Liu

Keyword(s):

Thermal Conductivity ◽

Thermoelectric Material ◽

Lattice Thermal Conductivity ◽

Phonon Frequency ◽

Electron Crystal

The prototype phonon-liquid electron-crystal β-Cu2Se has been ranked among the best thermoelectric material with its ultralow lattice thermal conductivity (κL).

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Analysis of Thermal Conductivity of LaFeAsO at Low Temperature

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1047.1 ◽

2014 ◽

Vol 1047 ◽

pp. 1-3

Author(s):

Netram Kaurav ◽

K.K. Choudhary

Keyword(s):

Thermal Conductivity ◽

Lattice Thermal Conductivity ◽

Phonon Scattering ◽

Phonon Frequency ◽

Density Wave ◽

Spin Density Wave ◽

Charge Carriers ◽

Scattering Mechanism ◽

Lattice Contribution ◽

Maximum Contribution

Thermal conductivity κ (T) of LaFeAsO is theoretically investigated below the spin density wave (SDW) anomaly. The lattice contribution to the thermal conductivity (κph) is discussed within the Debye-type relaxation rate approximation in terms of the acoustic phonon frequency and relaxation time below 150 K. The theory is formulated when heat transfer is limited by the scattering of phonons from defects, grain boundaries, charge carriers, and phonons. The lattice thermal conductivity dominates in LaFeAsO and is an artifact of strong phonon-impurity and-phonon scattering mechanism. Our result indicates that the maximum contribution comes from phonon scatters and various thermal scattering mechanisms provide a reasonable explanation for maximum appeared in κ (T).

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Quartic anharmonicity and ultra‐low lattice thermal conductivity of alkali antimonide compounds M 3 Sb ( M = K, Rb and Cs)

International Journal of Energy Research ◽

10.1002/er.6284 ◽

2020 ◽

Author(s):

Qi Zhong ◽

Zhenhong Dai ◽

Weiqiang Wang ◽

Yinchang Zhao ◽

Sheng Meng

Keyword(s):

Thermal Conductivity ◽

Lattice Thermal Conductivity ◽

Quartic Anharmonicity

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CONTRIBUTION OF LOW-FREQUENCY LONGITUDINAL PHONONS TO THE LATTICE THERMAL CONDUCTIVITY OF DIELECTRIC SOLIDS

Le Journal de Physique Colloques ◽

10.1051/jphyscol:1981674 ◽

1981 ◽

Vol 42 (C6) ◽

pp. C6-256-C6-258

Author(s):

R. Brito-Orta ◽

P. G. Klemens

Keyword(s):

Thermal Conductivity ◽

Lattice Thermal Conductivity ◽

Low Frequency ◽

Dielectric Solids

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Lattice Thermal Conductivity Modelling of a Diatomic Nanoscale Material

Nanoscience &Nanotechnology-Asia ◽

10.2174/2210681209666190423142040 ◽

2020 ◽

Vol 10 (5) ◽

pp. 602-609

Author(s):

Adil H. Awad

Keyword(s):

Thermal Conductivity ◽

Lattice Thermal Conductivity ◽

Phonon Scattering ◽

Correction Term ◽

Nanoscale Material ◽

New Approach ◽

Two Samples ◽

Conductivity Modelling ◽

Callaway Model

Introduction: A new approach for expressing the lattice thermal conductivity of diatomic nanoscale materials is developed. Methods: The lattice thermal conductivity of two samples of GaAs nanobeam at 4-100K is calculated on the basis of monatomic dispersion relation. Phonons are scattered by nanobeam boundaries, point defects and other phonons via normal and Umklapp processes. Methods: A comparative study of the results of the present analysis and those obtained using Callaway formula is performed. We clearly demonstrate the importance of the utilised scattering mechanisms in lattice thermal conductivity by addressing the separate role of the phonon scattering relaxation rate. The formulas derived from the correction term are also presented, and their difference from Callaway model is evident. Furthermore their percentage contribution is sufficiently small to be neglected in calculating lattice thermal conductivity. Conclusion: Our model is successfully used to correlate the predicted lattice thermal conductivity with that of the experimental observation.

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Local ferroelectric polarization switching driven by nanoscale distortions in thermoelectric $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$

Scientific Reports ◽

10.1038/s41598-021-96299-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Aastha Vasdev ◽

Moinak Dutta ◽

Shivam Mishra ◽

Veerpal Kaur ◽

Harleen Kaur ◽

...

Keyword(s):

Thermal Conductivity ◽

Figure Of Merit ◽

Room Temperature ◽

Lattice Thermal Conductivity ◽

Direct Evidence ◽

Temperature Dependent ◽

Force Microscopy ◽

Ferroelectric Domains ◽

Pdf Analysis ◽

Ferroelectric Transition Temperature

AbstractA remarkable decrease in the lattice thermal conductivity and enhancement of thermoelectric figure of merit were recently observed in rock-salt cubic SnTe, when doped with germanium (Ge). Primarily, based on theoretical analysis, the decrease in lattice thermal conductivity was attributed to local ferroelectric fluctuations induced softening of the optical phonons which may strongly scatter the heat carrying acoustic phonons. Although the previous structural analysis indicated that the local ferroelectric transition temperature would be near room temperature in $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te , a direct evidence of local ferroelectricity remained elusive. Here we report a direct evidence of local nanoscale ferroelectric domains and their switching in $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te using piezoeresponse force microscopy(PFM) and switching spectroscopy over a range of temperatures near the room temperature. From temperature dependent (250–300 K) synchrotron X-ray pair distribution function (PDF) analysis, we show the presence of local off-centering distortion of Ge along the rhombohedral direction in global cubic $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te . The length scale of the $${\text {Ge}}^{2+}$$ Ge 2 + off-centering is 0.25–0.10 Å near the room temperatures (250–300 K). This local emphatic behaviour of cation is the cause for the observed local ferroelectric instability, thereby low lattice thermal conductivity in $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te .

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