Edge-State Velocity and Coherence in a Quantum Hall Fabry-Pérot Interferometer

McClure, Douglas; Zhang, Yiming; Rosenow, Bernd; Levenson-Falk, E. M.; Marcus, C. M.; Pfeiffer, L. N.; West, K. W.

doi:10.1103/physrevlett.103.206806

Cited by 100 publications

(146 citation statements)

References 35 publications

(48 reference statements)

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“…In these examples, the nonlinear conductance exhibited the ubiquitous Coulomb 28,31 , and the oscillation periodicity with respect to magnetic field scaled inversely with the number of fully transmitted channels through the device 6,30,[32][33][34] . These two features clearly differ from our observation in the AB-FPI.…”

Section: Discussionmentioning

confidence: 99%

Robust electron pairing in the integer quantum hall effect regime

et al. 2015

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Electron pairing is a rare phenomenon appearing only in a few unique physical systems; for example, superconductors and Kondo-correlated quantum dots. Here, we report on an unexpected electron pairing in the integer quantum Hall effect regime. The pairing takes place within an interfering edge channel in an electronic Fabry-Perot interferometer at a wide range of bulk filling factors, between 2 and 5. We report on three main observations: high-visibility Aharonov-Bohm conductance oscillations with magnetic flux periodicity equal to half the magnetic flux quantum; an interfering quasiparticle charge equal to twice the elementary electron charge as revealed by quantum shot noise measurements, and full dephasing of the pairs' interference by induced dephasing of the adjacent inner edge channel-a manifestation of inter-channel entanglement. Although this pairing phenomenon clearly results from inter-channel interaction, the exact mechanism that leads to electronelectron attraction within a single edge channel is not clear. We believe that substantial efforts are needed in order to clarify these intriguing and unexpected findings.

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Section: Discussionmentioning

confidence: 99%

Robust electron pairing in the integer quantum hall effect regime

et al. 2015

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“…Such direct velocity measurements have been difficult with electron wave packets because gate pulses would also affect the background Fermi sea. Previous experiments [14,23,24] use other types of electron-transport data to estimate the electron velocity. Furthermore, electronelectron interactions can cause the formation of multiple collective modes traveling at different velocities, leading to decoherence [14,17,25].…”

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confidence: 99%

Time-of-Flight Measurements of Single-Electron Wave Packets in Quantum Hall Edge States

et al. 2016

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We report time-of-flight measurements on electrons traveling in quantum Hall edge states. Hot-electron wave packets are emitted one per cycle into edge states formed along a depleted sample boundary. The electron arrival time is detected by driving a detector barrier with a square wave that acts as a shutter. By adding an extra path using a deflection barrier, we measure a delay in the arrival time, from which the edgestate velocity v is deduced. We find that v follows 1=B dependence, in good agreement with theẼ ×B drift. The edge potential is estimated from the energy dependence of v using a harmonic approximation. DOI: 10.1103/PhysRevLett.116.126803 Electronic analogues of photonic quantum-optics experiments, so-called "electron quantum optics," can be performed using the beams of single-electron wave packets. The demonstration of entanglement and multiparticle interference with such wave packets would set the stage for quantum-technology applications such as quantum information processing [1]. Various theoretical proposals [2][3][4][5][6][7] and experimental realizations [8][9][10][11][12][13][14][15][16][17] employ quantum Hall edge states [18] as electron waveguides. The group velocity and dispersion relation of edge states are important parameters for understanding and controlling electron wave packet propagation. For edge magnetoplasmons, the velocity can be deduced by time-of-flight measurements with gate pulses [19][20][21][22]. Such direct velocity measurements have been difficult with electron wave packets because gate pulses would also affect the background Fermi sea. Previous experiments [14,23,24] use other types of electron-transport data to estimate the electron velocity. Furthermore, electronelectron interactions can cause the formation of multiple collective modes traveling at different velocities, leading to decoherence [14,17,25]. In order to perform the measurements of bare group velocity by time-resolved methods, we need a robust edge-state waveguide system where the interactions between the transmitted electrons and other electrons in the background can be suppressed.In this Letter, we demonstrate an experimental method for probing the bare edge-state velocity of electrons traveling in a depleted edge of a two-dimensional system. Electrons are emitted from a tunable-barrier single-electron pump [26][27][28] approximately 100 meV above the Fermi energy [13,29]. These electrons are injected into an edge where the background two-dimensional electron gas (2DEG) is depleted to avoid the influence of electron-electron interactions. The arrival time of these wave packets is detected by an energyselective detector barrier with a picosecond resolution [13,16]. The travel length between the source and detector is switched by a deflection barrier. The time of flight of the extra path is measured as a delay in the arrival time at the detector [30]. The edge-state velocity is calculated from the length of the extra path and the time of flight. We find that the edge-state velocity is inversely propor...

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“…The current-carrying edge channels in the FPI acquire a phase determined by the AB effect and the number of quasiparticles. This resultant phase arises from different velocities of the quasiparticles on different paths and can be controlled by either changing the magnetic field or the area of the interferometer 41 . The phase difference is strongly affected by the electron velocity and is an important transport parameter for interferometers.…”

Section: Incompressibilitymentioning

confidence: 99%

“…The phase difference is strongly affected by the electron velocity and is an important transport parameter for interferometers. To determine the edge channel velocity in the quantum Hall regime McClure et al 41 used interference to explain checkerboard patterns at a FPI geometry. Using the gradient of the confining potential it is straight forward to obtain electron velocities within a self-consistent screening theory.…”

Section: Incompressibilitymentioning

confidence: 99%

Formation of spin droplet atν=52in an asymmetric quantum dot under quantum Hall conditions

Atci

Siddiki

2017

Phys. Rev. B

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In this work, a quantum dot that is defined asymmetrically by electrostatic means induced on a GaAs/AlGaAs heterostructure is investigated to unravel the effect of geometric constrains on the formation of spin droplets under quantised Hall conditions. The incompressibility of exciting ν = 5/2 state is explored by solving the Schrödinger equation within spin density functional theory, where the confinement potential is obtained self-consistently utilising the Thomas-Fermi approximation. Our numerical investigations show that the spatial distribution of the ν = 2 incompressible strips and electron occupation in the second lowest Landau level considerably differ from the results of the laterally symmetric quantum dots. Our findings yield two important consequences, first the incompressibility of the intriguing ν = 5/2 state is strongly affected by the asymmetry, and second, since the Aharonov-Bohm interference patterns depend on the velocity of the particles, asymmetry yields an additional parameter to adjust the oscillation period, which imposes a boundary condition dependency in observing quasi-particle phases.

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Edge-State Velocity and Coherence in a Quantum Hall Fabry-Pérot Interferometer

Cited by 100 publications

References 35 publications

Robust electron pairing in the integer quantum hall effect regime

Robust electron pairing in the integer quantum hall effect regime

Time-of-Flight Measurements of Single-Electron Wave Packets in Quantum Hall Edge States

Formation of spin droplet atν=52in an asymmetric quantum dot under quantum Hall conditions

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