Title: 0.7 anomaly due to the Rashba interaction in a nonuniform electric field
Authors: Hsiao, J. H.
Liu, K. M.
Hsu, S. Y.
Hong, T. M.
電子物理學系
Department of Electrophysics
Keywords: Coulomb blockade;Kondo effect;quantum dots;quantum point contacts;resonant tunnelling
Issue Date: 1-Jan-2009
Abstract: We demonstrate that three conductance features, 0.5 and 0.7G(0) plateaus and a dip at 0.5G(0), observed in quantum point contacts (QPCs) can be consistently explained by the Rashba interaction in the nonuniform electric field created by the side gates along the transport direction. A quantity gamma is defined which depends on the extent of this nonuniformity and the electron density. A short QPC tends to have a small gamma. Only when gamma is large will the Rashba interaction produce a potential well deep enough to localize the electron. This provides the bound state that forms the Kondo resonance with the tunneling electrons. We propose to compare the medium/long QPC to small/large quantum dots, which are governed by the Kondo physics and the Coulomb blockade, respectively. The relation between 0.7 anomaly and the side-gate voltage, length of QPC, and temperature can all be determined to agree qualitatively with the experiments.
URI: http://dx.doi.org/10.1103/PhysRevB.79.033304
http://hdl.handle.net/11536/7774
ISSN: 1098-0121
DOI: 10.1103/PhysRevB.79.033304
Journal: PHYSICAL REVIEW B
Volume: 79
Issue: 3
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