Regensburg 2004 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 11: Nanoelektronik I: Quantenpunkte, -dr
ähte, -punktkontakte
TT 11.6: Vortrag
Dienstag, 9. März 2004, 10:45–11:00, H19
Negative differential resistance due to the resonance coupling of a quantum-dot dimer — •Shidong Wang1,2, Zouzou Sun1, Nelson Cue1, and Xiangrong Wang1 — 1Department of Physics, Hong Kong University of science and technolgy, HKSAR, China — 2Institut für Theoretische Physik, Universität Regensburg, 93040 Regensburg
We investigate the electron tunneling through a coupled quantum-dot dimer (a two quantum-dot system) under a dc bias. We find a new mechanism for the negative differential resistance (NDR) in a system with more than one quantum dots. We show that a peak in the I-V curves, that is, a NDR, occurs at low temperature when two discrete electronic states in the two quantum dots are aligned with each other. We call this coupling of two states the resonance coupling. We study also the dependence of the height and width of the I-V peak on the dot-dot coupling, e-e interaction, and the temperature. We find that the peak disappears due to thermal smearing effects at high temperature. We expect that this new NDR is useful in STM experiments. We hope that a better understanding of this resonance coupling effect may enhance the STM as a powerful probe not just for a regular surface, but also for a cluster structure.