We present low-temperature (0.2 < T < 10 K) transport measurements on semicontinuous films of bismuth which form a network of coupled Bi grains. By sequentially oxidizing such films we have observed a change in the character of transport that may be associated with the emergence of a finite charging energy and Coulomb blockade for single-electron tunneling between grains. This transition is manifested most dramatically as a divergence of the thermoelectric power with decreasing temperature. Magnetoresistance measurements indicate that the crossover in the thermopower occurs abruptly when the average oxide barrier resistance exceeds a fundamental value near łe2.
ASJC Scopus subject areas
- Physics and Astronomy(all)