Huge conductance peak caused by symmetry in double quantum dots.
We predict a huge interference effect contributing to the conductance through large ultraclean 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.
Whitney
Robert S
RS
Institut Laue-Langevin, 6 rue Jules Horowitz, B.P. 156, 38042 Grenoble, France.
Marconcini
P
P
Macucci
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