Electronic transmittance phase extracted from mesoscopic interferometers
Date
2012Source Title
Nanoscale Research Letters
Print ISSN
19317573
Volume
7
Language
English
Type
ArticleItem Usage Stats
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Abstract
The usual experimental set-up for measuring the wave function phase shift of electrons tunneling through a quantum dot (QD) embedded in a ring (i.e., the transmittance phase) is the so-called 'open' interferometer as first proposed by Schuster et al. in 1997, in which the electrons back-scattered at source and the drain contacts are absorbed by additional leads in order to exclude multiple interference. While in this case one can conveniently use a simple two-path interference formula to extract the QD transmittance phase, the open interferometer has also a number of draw-backs, such as a reduced signal and some uncertainty regarding the effects of the extra leads. Here we present a meaningful theoretical study of the QD transmittance phase in 'closed' interferometers (i.e., connected only to source and drain leads). By putting together data from existing literature and giving some new proofs, we show both analytically and by numerical simulations that the existence of phase lapses between consecutive resonances of the 'bare' QD is related to the signs of the corresponding Fano parameters - of the QD + ring system. More precisely, if the Fano parameters have the same sign, the transmittance phase of the QD exhibits a π lapse. Therefore, closed mesoscopic interferometers can be used to address the 'universal phase lapse' problem. Moreover, the data from already existing Fano interference experiments from Kobayashi et al. in 2003 can be used to infer the phase lapses. © 2012 Tolea et al.
Keywords
Aharonov-Bohm interferometersPhase lapse problem
Phase measurement
Aharonov-Bohm interferometers
Back-scattered
Drain contacts
Fano interference
Fano parameters
Mesoscopic interferometers
Multiple interferences
Phase lapse problem
Ring systems
Source and drains
Theoretical study
Transmittance phase
Interference suppression
Phase measurement
Superconducting materials
Interferometers
Permalink
http://hdl.handle.net/11693/21182Published Version (Please cite this version)
http://dx.doi.org/10.1186/1556-276X-7-568CCollections
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