Berlin 2008 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 35: Transport: Nanoelectronics I - Quantum Dots, Wires, Point Contacts 3
TT 35.15: Vortrag
Donnerstag, 28. Februar 2008, 18:00–18:15, H 3010
Electron Bunching in Stacks of Coupled Quantum Dots — •Sigmund Kohler1, Rafael Sánchez2, Peter Hänggi1, and Gloria Platero2 — 1Institut für Physik, Universität Augsburg — 2Instituto de Ciencia de Materiales, CSIC, Madrid, Spain
In recent measurements of the electrical current through transport channels that are formed by self-assembled double quantum dots, super-Poissonian noise has been observed [1]. In this system, two physical ingredients seems to play a crucial role, namely Coulomb interaction between electrons in neighbouring transport channels and, as well, the coupling of the electrons to substrate phonons. In a corresponding theoretical analysis [2], we study the transport properties of two double quantum dots in a parallel arrangement, in which the transport channels can block each other. Our results show that phonon emission and absorption, however, can suspend this blocking, which leads to “phonon-induced channel opening”. This also affects the shot noise: For asymmetric coupling between the dots and the respective lead, the current noise is sub-Poissonian for resonant tunnelling, but super-Poissonian in the vicinity of the resonances. The both experimentally and theoretically observed asymmetry of the peaks at low temperatures stems from spontaneous emission.
[1] P. Barthold, F. Hols, N. Maire, K. Pierz, and R. J. Haug, Phys. Rev. Lett. 96, 246804 (2006).
[2] R. Sánchez, S. Kohler, P. Hänggi, and G. Platero, arXiv:0706.2950 [cond-mat].