Seebeck Effect Fluctuations in Germanium

Fluctuations in the Seebeck effect or thermoelectric power of germanium single crystals have been observed. The Seebeck noise power spectrum varies as reciprocal frequency and may be quantitatively predicted from current-noise measurements. Carrier density fluctuations responsible for $\frac{1}{f}$ noise are also the source of Seebeck noise. The present results indicate that carrier fluctuations having a $\frac{1}{f}$ spectrum persist even in the absence of net dc current flow. Seebeck noise is also observed in low-noise specimens having nonohmic, noisy electrodes.