22 December 1998 Thermoelectric power of cuprates and other superconductors
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Abstract
Measurements by our group (and others) of the thermoelectric power in the normal state of cuprate superconductors show that thermopower, like the resistivity and Hall angle, shows a systematic pattern intimately related to the superconductivity. In the strongly overdoped regime, the transport properties show relatively conventional metallic behavior: for example, thermopower is often approximately proportional to temperature. As the hole concentration is then decreased and Tc increases to its maximum value, the in- plane thermopower shows an approximately temperature-indecent shift upwards to positive values, retaining a similar temperature coefficient of around -0.03 (mu) V/K2 for a wide range of cuprates. This continuity in the transition from more conventional behavior is easier to explain in the Van Hove scenario and by electron-phonon effects than by some exotic mechanisms for the origin of cuprate superconductivity. We also note that thermopower patterns surprisingly similar to that in the cuprates are seen in non-cuprate superconductors such as NbN, and also in the nonmagnetic cubic perovskite superconductor Ba1-xKxBiO3 (which, however, shows a nonlinearity at around 150 K). The thermopower of fullerene, Chevrel-phase compounds, NbN and disordered metal superconductors shows a low-temperature change of slope in good agreement with electron-phonon renormalization, demonstrating that thermopower can in many cases be used as a probe of the electron-phonon interaction.
© (1998) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Alan B. Kaiser, Alan B. Kaiser, G. C. McIntosh, G. C. McIntosh, "Thermoelectric power of cuprates and other superconductors", Proc. SPIE 3481, Superconducting and Related Oxides: Physics and Nanoengineering III, (22 December 1998); doi: 10.1117/12.335866; https://doi.org/10.1117/12.335866
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