Seminar on Disorder and strong electron correlations: "Symmetry causes a huge conductance peak in double quantum dots"
Starts 2 Apr 2009 12:00
Ends 2 Apr 2009 20:00
Central European Time
Leonardo da Vinci Building Seminar Room
Strada Costiera, 11
I - 34151 Trieste (Italy)
We predict a huge interference effect contributing to the conductance through large ultra-clean quantum dots of chaotic shape. When a double-dot structure is made such that the dots are the mirror-image of each other, constructive interference can make a tunnel barrier located on the symmetry axis effectively transparent. We show (via theoretical analysis and numerical simulation) that this effect can be orders of magnitude larger than the well-known universal conductance fluctuations and weak-localization (both less than a conductance quantum). A small magnetic field destroys the effect, massively reducing the double-dot conductance; thus a magnetic field detector is obtained, with a similar sensitivity to a SQUID, but requiring no superconductors.
[Robert S. Whitney, P. Marconcini, M. Macucci, to appear in Phys. Rev. Lett. (2009) arXiv:0902.3099]
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