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arXiv · 2010.11404

Electrical and Thermal Transport Properties of the beta-Pyrochlore Oxide CsW2O6

Yoshihiko Okamoto·Kenta Niki·Rikuto Mitoka·Koshi Takenaka
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Abstract

We report the electrical resistivity, thermoelectric power, and thermal conductivity of single-crystalline and sintered samples of the 5d pyrochlore oxide CsW2O6. The electrical resistivity of the single crystal is 3 mohm cm at 295 K and gradually increases with decreasing temperature above 215 K (Phase I). The thermoelectric power of the single-crystalline and sintered samples shows a constant value of approximately -60 uV K-1 in Phase I. These results reflect that the electron conduction by W 5d electrons in Phase I is incoherent and in the hopping regime, although a band gap does not open at the Fermi level. The thermal conductivity in Phase I of both samples is considerably low, which might be due to the rattling of Cs+ ions. In Phase II below 215 K, the electrical resistivity and the absolute value of thermoelectric power of both samples strongly increase with decreasing temperature, corresponding to a transition to a semiconducting state with a band gap open at the Fermi level, while the thermal conductivity in Phase II is smaller than that in Phase I.

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Yoshihiko Okamoto, Kenta Niki, Rikuto Mitoka, Koshi Takenaka. 2020-10-22. Electrical and Thermal Transport Properties of the beta-Pyrochlore Oxide CsW2O6. https://doi.org/10.7566/jpsj.89.124710

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