Dresden 2003 – scientific programme
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HL: Halbleiterphysik
HL 48: Quantenpunke und -dr
ähte: Transporteigenschaften III
HL 48.2: Talk
Thursday, March 27, 2003, 15:30–15:45, BEY/81
Negative differential resistance and large enhancement of shot–noise in two capacitively coupled molecular–size single electron transistors. — •Grzegorz Michałek1,2 and Bogdan R. Bułka2 — 1I. Institut für Theoretische Physik, Universität Hamburg, Jungiusstraße 9, 20355 Hamburg, Germany — 2Institute of Molecular Physics, Polish Academy of Sciences, ul. Smoluchowskiego 17, 60-179 Poznań, Poland
The steady state transport properties and the shot–noise in the system, which is composed of two single electron transistors connected in parallel were studied in the framework of the sequential tunneling approach. Our consideration were restricted to electron tunneling through the atomic–sized spacers (dots) of the transistors, which means each of them contain only a single energy level. A special attention was focused on the negative differential resistance phenomenon, which appears due to the Coulomb interactions between charges accumulated on both dots. It was shown that interactions can lead to an enhancement of the shot–noise. Spectral decomposition analysis showed two contribution to the current noise: high–frequency charge fluctuations and low–frequency polarization fluctuations. It was found that the activation of the polarization noise (low frequency fluctuations) is responsible for a strong enhancement of the current noise.