title: Role of interactions in an electronic Fabry-Perot interferometer operating in the quantum Hall effect regime.
abstract: Interference of edge channels is expected to be a prominent tool for studying statistics of charged quasiparticles in the quantum Hall effect (QHE). We present here a detailed study of an electronic Fabry-Perot interferometer (FPI) operating in the QHE regime [C. Chamon, et al. (1997) Phys Rev B 55:2331-2334], with the phase of the interfering quasiparticles controlled by the Aharonov-Bohm effect. Our main finding is that Coulomb interactions among the electrons dominate the interference, even in a relatively large area FPI, leading to a strong dependence of the area enclosed by the interference loop on the magnetic field. In particular, for a composite edge structure, with a few independent edge channels propagating along the edge, interference of the outmost edge channel (belonging to the lowest Landau level) was insensitive to magnetic field-suggesting a constant enclosed flux. However, when any of the inner edge channels interfered, the enclosed flux decreased when the magnetic field increased. By intentionally varying the enclosed area with a biased metallic gate and observing the periodicity of the interference pattern, charges e (for integer filling factors) and e/3 (for a fractional filling factor) were found to be expelled from the FPI. Moreover, these observations provided also a novel way of detecting the charge of the interfering quasiparticles.
authors.affiliation: Braun Center for Submicron Research, Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 76100, Israel. nissim.ofek@weizmann.ac.il
authors.forename: Nissim
authors.initials: N
authors.lastname: Ofek
authors.forename: Aveek
authors.initials: A
authors.lastname: Bid
authors.forename: Moty
authors.initials: M
authors.lastname: Heiblum
authors.forename: Ady
authors.initials: A
authors.lastname: Stern
authors.forename: Vladimir
authors.initials: V
authors.lastname: Umansky
authors.forename: Diana
authors.initials: D
authors.lastname: Mahalu