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Abstract We report the topological phase and thermoelectric properties of bialkali bismuthide compounds (Na, K) 2 RbBi, as yet hypothetical. The topological phase transitions of these compounds under hydrostatic pressure are investigated. The calculated topological surface states and Z 2 topological index confirm the nontrivial topological phase. The electronic properties and transport coefficients are obtained using the density functional theory combined with the Boltzmann transport equation. The relaxation times are determined using the deformation potential theory to calculate the electronic thermal and electrical conductivity. The calculated mode Grüneisen parameters are substantial, indicating strong anharmonic acoustic phonons scattering, which results in an exceptionally low lattice thermal conductivity. These compounds also have a favorable power factor leading to a relatively flat p-type figure-of-merit over a broad temperature range. Furthermore, the mechanical properties and phonon band dispersions show that these structures are mechanically and dynamically stable. Therefore, they offer excellent candidates for practical applications over a wide range of temperatures.
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Electrostatic modulation of thermoelectric transport properties of 2H-MoTe 2
Two-dimensional layered transition metal dichalcogenides are potential thermoelectric candidates with application in on-chip integrated nanoscale cooling and power generation. Here, we report a comprehensive experimental and theoretical study on the in-plane thermoelectric transport properties of thin 2H-MoTe2 flakes prepared in field-effect transistor geometry to enable electrostatic gating and modulation of the electronic properties. The thermoelectric power factor is enhanced by up to 45% using electrostatic modulation. The in-plane thermal conductivity of 9.8 ± 3.7 W m−1 K−1 is measured using the heat diffusion imaging method in a 25 nm thick flake. First-principles calculations are used to obtain the electronic band structure, phonon band dispersion, and electron–phonon scattering rates. The experimental electronic properties are in agreement with theoretical results obtained within energy-dependent relaxation time approximation. The thermal conductivity is evaluated using both the relaxation time approximation and the full iterative solution to the phonon Boltzmann transport equation. This study establishes a framework to quantitively compare first-principle-based calculations with experiments in 2D layered materials.
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- Award ID(s):
- 2230352
- PAR ID:
- 10556280
- Publisher / Repository:
- Royal Society of Chemistry
- Date Published:
- Journal Name:
- Energy Advances
- Volume:
- 2
- Issue:
- 11
- ISSN:
- 2753-1457
- Page Range / eLocation ID:
- 1882 to 1892
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/D3YA00316G
