Low-temperature anharmonicity and the thermal conductivity of cesium iodide

Wei, Bin; Yu, Xiaoxia; Yang, Chao; Rao, Xin; Wang, Xueyun; Chi, Songxue; Sun, Xiaofeng; Hong, Jiawang

doi:10.1103/physrevb.99.184301

Cited by 14 publications

(12 citation statements)

References 47 publications

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“…2 shows the calculated phonon dispersions for all studied compounds, which agree well with available experimental data. [7,29,[47][48][49][50][51][52][53][54][55][56] The general shape of phonon dispersions in NaCltype (Figs. 2a-i) and CsCl-type (Figs.…”

Section: Resultsmentioning

confidence: 99%

“…[3] These prominent properties associate closely with phonon thermal transport properties, such as lattice vibrations [4][5] and thermal conductivities. [6][7] For most compounds in alkali halides, the thermal conductivities are relatively low, and the values at room temperature range from 1 to 7 W/mK. [8] Previous works have been performed to investigate the thermal properties of alkali halides using classical theoretical methods.…”

Section: Introductionmentioning

confidence: 99%

“…[15][16][17] Recent theoretical reports mainly take alkali halides as models to verify the accuracy of the improved prediction of thermal conductivity, [18][19] but the inherent thermal transport of alkali halides is rarely concerned. [7,[20][21][22] Therefore, a systemic revisit to the thermal transport properties in alkali halides by stateof-art computational techniques is of urgent necessity.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Anomalous Thermal Conductivity Induced by High Dispersive Optical Phonons in Rubidium and Cesium Halides

Chang¹,

Yuan²,

Li³

et al. 2022

ES Energy Environ.

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Knowledge of lattice dynamics is essential for understanding the physical properties of materials and optimizing the performance for applications. Alkali halides (MX, M=Na, K, Rb, and Cs; X=Cl, Br, and I) have been widely recognized for their simple crystal structures and low thermal conductivities. At room temperature, the thermal conductivity (κ) of RbBr is nearly twice as large as that of RbCl and RbI, while the thermal conductivities of three compounds in CsX halides are comparable. These thermal conductivity trends with increased atomic mass are significantly different from the common sense that the thermal conductivity conventionally decreases with the increasing atomic mass and decreasing electronegativity difference. However, little attention has been paid to the microscopic mechanism of these anomalous thermal conductions in RbX and CsX. Here, we report a systematic investigation of the thermal transport properties in alkali halides by the Boltzmann transport equation based on first-principles calculations. The results show that the anomalous thermal conductivity trends of RbX and CsX mainly attribute to the disparity of optical phonons in each compound. The more dispersive the optical phonons, the greater their contribution to the thermal conductivity, and thus the thermal conductivities of compounds with heavier atoms are enhanced. The disparity of optical phonons originates from the mass difference in the compound. Our work offers deeper insight into the unusual phonon thermal transport phenomenon in alkali halides, and provides fundamental reference for rooting the thermal conductivities in related functional materials and finding novel materials with thermal conduction beyond the conventional cognition.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Anomalous Thermal Conductivity Induced by High Dispersive Optical Phonons in Rubidium and Cesium Halides

Chang¹,

Yuan²,

Li³

et al. 2022

ES Energy Environ.

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“…High-quality GaN single crystals (un-doped, n-type, MTI Corporation [36]) used in this work were grown by the hydride vapor phase epitaxy (HVPE)-based method with low dislocation density (< 1  10 7 cm -2 ) (Fig. S1c).…”

Section: Gan Single Crystal Samplesmentioning

confidence: 99%

Matryoshka phonon twinning in α-GaN

et al. 2021

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Understanding lattice dynamics is crucial for effective thermal management in electronic devices because phonons dominate thermal transport in most semiconductors. α-GaN has become a focus of interest as one of the most important third-generation power semiconductors, however, the knowledge on its phonon dynamics remains limited. Here we show a Matryoshka phonon dispersion of α-GaN with the complementary inelastic X-ray and neutron scattering techniques and the first-principles calculations. Such Matryoshka twinning throughout the basal plane of the reciprocal space is demonstrated to amplify the anharmonicity of the related phonons through creating abundant three-phonon scattering channels and cutting the lifetime of affected modes by more than 50%. Such phonon topology contributes to reducing the in-plane thermal transport, thus the anisotropic thermal conductivity of α-GaN. The results not only have implications for engineering the thermal performance of α-GaN, but also offer valuable insights on the role of anomalous phonon topology in thermal transport of other technically semiconductors.

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“…For example, in the leading thermoelectric material SnSe, it was recently found that the coupled instability of electronic orbitals and lattice dynamics is the origin of its strong anharmonicity and ultralow thermal conductivity [39,48]. In the typical ionic compound, cesium halides (e.g., CsCl, CsBr, and CsI), a lowtemperature anharmonicity was found with anharmonic Cs displacements and short phonon lifetime, compared with the anharmonic behavior commonly occurring at higher temperatures [49,50]. The remarkable progress of phonon an-harmonicity promotes a deep understanding of thermoelectrics [39,46,48], ferroelectrics [51,52], multiferroics [53][54][55], high-T c superconductors [56][57][58], etc.…”

Section: Introductionmentioning

confidence: 99%

Phonon anharmonicity: a pertinent review of recent progress and perspective

Wei

Sun

et al. 2021

Sci. China Phys. Mech. Astron.

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Anharmonic lattice vibrations play pivotal roles in the thermal dynamics in condense matters and affect how the atoms interact and conduct heat. An in-depth understanding of the microscopic mechanism of phonon anharmonicity in condensed systems is critical for developing better functional and energy materials. In recent years, various novel behaviors in condense matters driven by phonon anharmonic effects were discovered, such as soft mode phase transition, negative thermal expansion (NTE), multiferroicity, ultralow thermal conductivity (κ), high thermal resistance, and high-temperature superconductivity. These properties have endowed anharmonicity with many promising applications and provided remarkable opportunities for developing "Anharmonicity Engineering"-regulating heat transport towards excellent performance in materials. In this work, we review the recent development of studies on phonon anharmonic effect and summarize its origin, mechanism, research methods, and applications. Besides, the remaining challenges, future trends, and prospects of phonon anharmonicity are also discussed.

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Low-temperature anharmonicity and the thermal conductivity of cesium iodide

Cited by 14 publications

References 47 publications

Anomalous Thermal Conductivity Induced by High Dispersive Optical Phonons in Rubidium and Cesium Halides

Anomalous Thermal Conductivity Induced by High Dispersive Optical Phonons in Rubidium and Cesium Halides

Matryoshka phonon twinning in α-GaN

Phonon anharmonicity: a pertinent review of recent progress and perspective

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