THERMOELECTRIC POWER OF POLYCRYSTALLINE BISMUTH: PHONON DRAG SIZE EFFECT.
Final scientific rept. 1 Dec 64-31 Dec 65,
LOUVAIN UNIV (BELGIUM)
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It was found that the thermoelectric power of polycrystalline bismuth increases with decreasing thickness at room temperature. Parallel galvanomagnetic and resistivity measurements indicate that the mean free paths of the charge carriers remain unchanged in the range of thickness investigated. Applying Herrings simplified formula, combined with the law of emfs in parallel extended to three band conduction, it was found that a phonon-drag mechanism could explain the observed increase in TEP and the order of magnitude of the effect. The expected variation of the diffusion thermoelectric power with temperature in the range 80-300K was also computed, using the correct band structure and the temperature dependence of the density of free carriers. Besides, it was found that at 80K, the magnetoresistance is not the same for thin foils, whether the magnetic field is perpendicular or parallel to the surface of the foil. Some interesting features are noted about the low-field galvanomagnetic coefficients. Author
- Electricity and Magnetism
- Solid State Physics