Measuring lattice thermal conductivity of Bi1-xSbx enabled by external magnetic field
Minimizing lattice thermal conductivity (κL) is one of the most successful strategies for enhancing thermoelectrics. Existing experimental approach for κL-determination largely depend on model approximations for the electronic component (κE) with a subtraction from the measured total thermal conduct...
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Published in | Materials today physics Vol. 45 |
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Main Authors | , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Elsevier Ltd
01.06.2024
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Subjects | |
Online Access | Get full text |
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Summary: | Minimizing lattice thermal conductivity (κL) is one of the most successful strategies for enhancing thermoelectrics. Existing experimental approach for κL-determination largely depend on model approximations for the electronic component (κE) with a subtraction from the measured total thermal conductivity (κ = κL+κE). However, the approximations (e.g. Wiedemann-Franz law) may not always be accurate particularly for materials with complicated band structures. Accurate κL-determination, not only characterizing the fundamental capability in heat conduction but also providing the insight of thermal functional materials, is still challenging. In this work, we utilize the magneto-thermoelectric effect under a magnetic field to suppress κE whereas κL is nearly unaffected. This allows for direct κL-measurement in materials that particularly have high carrier mobility. It is demonstrated in Bi1-xSbx single crystals that longitudinal κE can be sufficiently minimized to enable direct measurement in longitudinal κL at T < 100 K under a magnetic field of 5 T. It is revealed that the commonly used single Kane band (SKB) model approximations would lead to a 30 % overestimation in κL. The method proposed here enables a pathway of κL-determination for understanding the phonon transport in materials with complicated band structure.
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•This work enables a removal of electronic components, offering a method for directlattice thermal conductivity measurements.•A 30 % overestimation in lattice thermal conductivity for Bi1-xSbx , according to the commonly used single band model, is revealed.•The T−1 decay at high temperatures for high-field thermal conductivity suggests the dominance of Umklapp scattering of phonons. |
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ISSN: | 2542-5293 2542-5293 |
DOI: | 10.1016/j.mtphys.2024.101460 |