Dresden 2009 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 11: Transport: Nanoelectronics I - Quantum Dots and Wires, Point Contacts 2
TT 11.1: Vortrag
Montag, 23. März 2009, 14:00–14:15, HSZ 301
Pair tunneling resonance in the single-electron transport regime — •Martin Leijnse1,3, Maarten Wegewijs1,2,3, and Herbert Schoeller1,3 — 1Institut für Theoretische Physik A, RWTH Aachen, 52056 Aachen, Germany — 2Institut für Festkörper-Forschung - Theorie 3, Forschungszentrum Jülich, 52425 Jülich, Germany — 3JARA-Fundementals of Future Information Technology
We predict a new resonance in non-linear transport through strongly interacting quantum dots, originating from the coherent tunneling of electron pairs (PT). The PT resonance shows up as a peak in the derivative of the differential conductance, d2I/dV2, in the single-electron transport (SET) regime. The position is determined by the electrochemical potential of one electrode matching the average of two subsequent charge addition energies. Using 4th order perturbation theory in the tunneling coupling[1] for a single level quantum dot (Anderson model), we present an analytic expression for the peak shape, which reveals the bosonic nature of the charge transfer. Awareness of the PT resonance can be crucial for interpretation of experimental low-temperature transport spectroscopy data of semi-conducting, carbon nanotube, or single molecule quantum dots, since it can easily be mistaken for a weak SET resonance judging only by the voltage dependence of its position. We show that the PT resonance can be distinguished from SET by its anomalous temperature- and magnetic field dependence, peak shape and shot-noise signature.
[1] M. Leijnse, M. R. Wegewijs, PRB (in print), arXiv:0807.4027.