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Liu B, Kelsall J, Ward DJ, Jardine AP. Experimental Characterization of Defect-Induced Phonon Lifetime Shortening. PHYSICAL REVIEW LETTERS 2024; 132:056202. [PMID: 38364135 DOI: 10.1103/physrevlett.132.056202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Revised: 11/18/2023] [Accepted: 12/15/2023] [Indexed: 02/18/2024]
Abstract
We present the first direct experimental measurement of defect-induced lifetime shortening of acoustic surface phonons. Defects are found to contribute a temperature-independent component to the linewidths of Rayleigh wave phonons on a Ni(111) surface. We also characterized the increase in phonon scattering with both surface defect density and phonon wave vector. A quantitative estimate of the scattering rate between phonon modes and surface line defects is extracted from the experimental data for the first time.
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Affiliation(s)
- Boyao Liu
- Cavendish Laboratory, University of Cambridge, 19 J J Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Jack Kelsall
- Cavendish Laboratory, University of Cambridge, 19 J J Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - David J Ward
- Cavendish Laboratory, University of Cambridge, 19 J J Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Andrew P Jardine
- Cavendish Laboratory, University of Cambridge, 19 J J Thomson Avenue, Cambridge CB3 0HE, United Kingdom
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2
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Hou MD, Zhou XW, Liu B. Beryllium oxide utilized in nuclear reactors: Part I: Application history, thermal properties, mechanical properties, corrosion behavior and fabrication methods. NUCLEAR ENGINEERING AND TECHNOLOGY 2022. [DOI: 10.1016/j.net.2022.07.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Ji S, Grånäs O, Weissenrieder J. Manipulation of Stacking Order in Td-WTe 2 by Ultrafast Optical Excitation. ACS NANO 2021; 15:8826-8835. [PMID: 33913693 PMCID: PMC8291768 DOI: 10.1021/acsnano.1c01301] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 04/27/2021] [Indexed: 06/12/2023]
Abstract
Subtle changes in stacking order of layered transition metal dichalcogenides may have profound influence on the electronic and optical properties. The intriguing electronic properties of Td-WTe2 can be traced to the break of inversion symmetry resulting from the ground-state stacking sequence. Strategies for perturbation of the stacking order are actively pursued for intentional tuning of material properties, where optical excitation is of specific interest since it holds the potential for integration of ultrafast switches in future device designs. Here we investigate the structural response in Td-WTe2 following ultrafast photoexcitation by time-resolved electron diffraction. A 0.23 THz shear phonon, involving layer displacement along the b axis, was excited by a 515 nm laser pulse. Pump fluences in excess of a threshold of ∼1 mJ/cm2 result in formation, with an ∼5 ps time constant, of a new stacking order by layer displacement along the b axis in the direction toward the centrosymmetric 1T* phase. The shear displacement of the layers increases with pump fluence until saturation at ∼8 pm. We demonstrate that the excitation of the shear phonon and the stabilization of the metastable phase are decoupled when using an optical pump as evidenced by observation of a transition also in samples with a pinned shear phonon. The results are compared to dynamic first-principles simulations and the transition is interpreted in terms of a mechanism where transient local disorder is prominent before settling at the atomic positions of the metastable phase. This interpretation is corroborated by results from diffuse scattering. The correlation between excitation of intralayer vibrations and interlayer interaction demonstrates the importance of including both short- and long-range interactions in an accurate description of how optical fields can be employed to manipulate the stacking order in 2-dimensional transition metal dichalcogenides.
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Affiliation(s)
- Shaozheng Ji
- Materials
and Nano Physics, School of Engineering Sciences, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
| | - Oscar Grånäs
- Division
for Materials Theory, Department of Physics and Astronomy, Uppsala University, SE-751 20 Uppsala, Sweden
| | - Jonas Weissenrieder
- Materials
and Nano Physics, School of Engineering Sciences, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
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Yang G, Sang L, Li M, Kazi Nazrul Islam SM, Yue Z, Liu L, Li J, Mitchell DRG, Ye N, Wang X. Enhancing the Thermoelectric Performance of Polycrystalline SnSe by Decoupling Electrical and Thermal Transport through Carbon Fiber Incorporation. ACS APPLIED MATERIALS & INTERFACES 2020; 12:12910-12918. [PMID: 32101408 DOI: 10.1021/acsami.0c00873] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Thermoelectric (TE) materials have attracted extensive interest because of their ability to achieve direct heat-to-electricity conversion. They provide an appealing renewable energy source in a variety of applications by harvesting waste heat. The record-breaking figure of merit reported for single crystal SnSe has stimulated related research on its polycrystalline counterpart. Boosting the TE conversion efficiency requires increases in the power factor and decreases in thermal conductivity. It is still a big challenge, however, to optimize these parameters independently because of their complex interrelationships. Herein, we propose an innovative approach to decouple electrical and thermal transport by incorporating carbon fiber (CF) into polycrystalline SnSe. We show that the incorporation of highly conductive CF can successfully enhance the electrical conductivity, while greatly reducing the thermal conductivity of polycrystalline SnSe. As a result, a high TE figure-of-merit (zT) of 1.3 at 823 K is obtained in p-type SnSe/CF composite polycrystalline materials. Furthermore, SnSe samples incorporated with CFs exhibit superior mechanical properties, which are favorable for device fabrication applications. Our results indicate that the dispersion of CF can be a good way to greatly improve both TE and mechanical performance.
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Affiliation(s)
- Guangsai Yang
- Institute for Superconducting and Electronic Materials, Australian Institute for Innovative Materials, University of Wollongong, North Wollongong, New South Wales 2500, Australia
- Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, PR China
| | - Lina Sang
- Institute for Superconducting and Electronic Materials, Australian Institute for Innovative Materials, University of Wollongong, North Wollongong, New South Wales 2500, Australia
- Australian Research Council Centre of Excellence in Future Low-Energy Electronics Technologies, University of Wollongong, Wollongong, 2500 Australia
| | - Meng Li
- Institute for Superconducting and Electronic Materials, Australian Institute for Innovative Materials, University of Wollongong, North Wollongong, New South Wales 2500, Australia
| | - Sheik Md Kazi Nazrul Islam
- Institute for Superconducting and Electronic Materials, Australian Institute for Innovative Materials, University of Wollongong, North Wollongong, New South Wales 2500, Australia
| | - Zengji Yue
- Institute for Superconducting and Electronic Materials, Australian Institute for Innovative Materials, University of Wollongong, North Wollongong, New South Wales 2500, Australia
- Australian Research Council Centre of Excellence in Future Low-Energy Electronics Technologies, University of Wollongong, Wollongong, 2500 Australia
| | - Liqiang Liu
- Faculty of Materials Engineering, Shandong Jianzhu University, Jinan, Shandong 250101, PR China
| | - Jianing Li
- Faculty of Materials Engineering, Shandong Jianzhu University, Jinan, Shandong 250101, PR China
| | - David R G Mitchell
- Electron Microscopy Centre, Australian Institute for Innovative Materials, University of Wollongong, North Wollongong, New South Wales 2500, Australia
| | - Ning Ye
- Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, PR China
| | - Xiaolin Wang
- Institute for Superconducting and Electronic Materials, Australian Institute for Innovative Materials, University of Wollongong, North Wollongong, New South Wales 2500, Australia
- Australian Research Council Centre of Excellence in Future Low-Energy Electronics Technologies, University of Wollongong, Wollongong, 2500 Australia
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Kumar VN, Hayakawa Y, Udono H, Inatomi Y. An Approach to Optimize the Thermoelectric Properties of III–V Ternary InGaSb Crystals by Defect Engineering via Point Defects and Microscale Compositional Segregations. Inorg Chem 2019; 58:11579-11588. [DOI: 10.1021/acs.inorgchem.9b01430] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Velu Nirmal Kumar
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Japan
| | - Yasuhiro Hayakawa
- Research Institute of Electronics, Shizuoka University, Hamamatsu, Japan
| | - Haruhiko Udono
- Faculty of Engineering, Ibaraki University, Hitachi, Japan
| | - Yuko Inatomi
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Japan
- School of Physical Sciences, SOKENDAI (The Graduate University for Advanced Studies), Sagamihara, Japan
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Ma H, Tian Z. Significantly High Thermal Rectification in an Asymmetric Polymer Molecule Driven by Diffusive versus Ballistic Transport. NANO LETTERS 2018; 18:43-48. [PMID: 29215898 DOI: 10.1021/acs.nanolett.7b02867] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Tapered bottlebrush polymers have novel nanoscale polymer architecture. Using nonequilibrium molecular dynamics simulations, we showed that these polymers have the unique ability to generate thermal rectification in a single polymer molecule and offer an exceptional platform for unveiling different heat conduction regimes. In sharp contrast to all other reported asymmetric nanostructures, we observed that the heat current from the wide end to the narrow end (the forward direction) in tapered bottlebrush polymers is smaller than that in the opposite direction (the backward direction). We found that a more disordered to less disordered structural transition within tapered bottlebrush polymers is essential for generating nonlinearity in heat conduction for thermal rectification. Moreover, the thermal rectification ratio increased with device length, reaching as high as ∼70% with a device length of 28.5 nm. This large thermal rectification with strong length dependence uncovered an unprecedented phenomenon-diffusive thermal transport in the forward direction and ballistic thermal transport in the backward direction. This is the first observation of radically different transport mechanisms when heat flow direction changes in the same system. The fundamentally new knowledge gained from this study can guide exciting research into nanoscale organic thermal diodes.
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Affiliation(s)
- Hao Ma
- Department of Mechanical Engineering and ‡Macromolecules Innovation Institute, Virginia Tech , Blacksburg, Virginia 24061, United States
| | - Zhiting Tian
- Department of Mechanical Engineering and ‡Macromolecules Innovation Institute, Virginia Tech , Blacksburg, Virginia 24061, United States
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