Beating of Aharonov-Bohm oscillations in a closed-loop interferometer

One of the points at issue with closed-loop-type interferometers is beating in the Aharonov-Bohm (AB) oscillations. Recent observations suggest the possibility that the beating results from the Berry-phase pickup by the conducting electrons in materials with the strong spin-orbit interaction (SOI)....

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Bibliographic Details
Published in:Physical review. B, Condensed matter and materials physics Condensed matter and materials physics, 2007-07, Vol.76 (3), Article 035110
Main Authors: Jo, Sanghyun, Khym, Gyong Luck, Chang, Dong-In, Chung, Yunchul, Lee, Hu-Jong, Kang, Kicheon, Mahalu, Diana, Umansky, Vladimir
Format: Article
Language:English
Subjects:
AHARONOV-BOHM EFFECT
ALUMINIUM COMPOUNDS
CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
ELECTRIC CONDUCTIVITY
ELECTRON GAS
GALLIUM ARSENIDES
INTERFEROMETERS
L-S COUPLING
MAGNETIC FIELDS
MATERIALS SCIENCE
OSCILLATIONS
PEAKS
QUANTUM MECHANICS
SEMICONDUCTOR MATERIALS
TWO-DIMENSIONAL CALCULATIONS
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Summary:One of the points at issue with closed-loop-type interferometers is beating in the Aharonov-Bohm (AB) oscillations. Recent observations suggest the possibility that the beating results from the Berry-phase pickup by the conducting electrons in materials with the strong spin-orbit interaction (SOI). In this study, we also observed beats in the AB oscillations in a gate-defined closed-loop interferometer fabricated on a GaAs/Al{sub 0.3}Ga{sub 0.7}As two-dimensional electron-gas heterostructure. Since this heterostructure has very small SOI, the picture of the Berry-phase pickup is ruled out. The observation of beats in this study, with the controllability of forming a single transverse subband mode in both arms of our gate-defined interferometer, also rules out the often-claimed multiple transverse subband effect. It is observed that nodes of the beats with an h/2e period exhibit a parabolic distribution for varying the side gate. These results are shown to be well interpreted, without resorting to the SOI effect, by the existence of two-dimensional multiple longitudinal modes in a single transverse subband. The Fourier spectrum of measured conductance, despite showing multiple h/e peaks with the magnetic-field dependence that are very similar to that from strong-SOI materials, can also be interpreted as the two-dimensional multiple-longitudinal-modes effect.
ISSN:1098-0121
1550-235X
DOI:10.1103/PhysRevB.76.035110