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Aharonov-Bohm conductance through a single-channel quantum ring
Igor Gornyi, Karlsruhe Institute of Technology
05.11.2010 at 10:15
Abstract:
We study the effect of electron-electron interaction on the Aharonov-Bohm
effect in a single-channel ring. We demonstrate that interactions lead to
profound and unusual effects in transport through a quantum-ring
interferometer tunnel-coupled to the leads. The physics behind the
peculiar behavior of the conductance is the blocking of the tunneling
current by the circular current inside the ring. We call this phenomenon
"Persistent-Current Blockade". Specifically, we find that the conductance
as a function of magnetic flux shows a series of interaction-induced
resonances that---in contrast to Coulomb blockade oscillations---survive
thermal averaging. The period of the series is given by the interaction
strength, whereas the width of the resonances is governed by dephasing.
The main mechanism of dephasing is due to tunneling-induced fluctuations
of the circular current ("Zero-Mode Dephasing"). The dephasing rate is
proportional to the tunneling rate and, remarkably, does not depend on the
interaction constant. Our predictions can be verified by measuring the
conductance of a semiconductor nanoring or a single coil of carbon
nanotube.
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