Competition between h/e and h/2e oscillations in a semiconductor Aharonov-Bohm interferometer

Mur, L.C. and Harmans, C.J.P.M. and Wiel van der, W.G. (2008) Competition between h/e and h/2e oscillations in a semiconductor Aharonov-Bohm interferometer. New Journal of Physics, 10 . 073031. ISSN 1367-2630

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Abstract:	The magnetoresistance of a quasi-ballistic Aharonov-Bohm (AB) ring defined in the two-dimensional electron gas (2DEG) of an InP/In0.8Ga0.2As quantum well is studied. The ring is connected to an Al contact on one side and to a 2DEG reservoir at the other side. Two distinct magnetic field regimes can be identified. At magnetic field values where time-reversal symmetry (TRS) is broken, AB oscillations are observed. Besides oscillations with h/e periodicity, we also observe higher harmonics with h/2e and h/3e periods. In the low-magnetic field range, where TRS is preserved, the AB oscillations are alternately dominated by the h/e or h/2e component, depending on the bias voltage. Although Al is superconducting at these low magnetic fields, no evidence is found that the observed AB oscillations are related to the proximity of the superconductor. The bias voltage dependence is qualitatively described in terms of a 1D scattering model.
Item Type:	Article
Copyright:	© 2008 IOP Publishing and Deutsche Physikalische Gesellschaft
Faculty:	Electrical Engineering, Mathematics and Computer Science (EEMCS)
Research Group:	Nano-Electronics (NE)
Link to this item:	http://purl.utwente.nl/publications/59273
Official URL:	http://dx.doi.org/10.1088/1367-2630/10/7/073031
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