19 research outputs found
The Aharonov-Bohm Effect in the Fractional Quantum Hall Regime
We have investigated experimentally resonant tunnelling through
single-particle states formed around an antidot by a magnetic field, in the
fractional quantum Hall regime. For 1/3 filling factor around the antidot,
Aharonov-Bohm oscillations are observed with the same magnetic field period as
in the integer quantum Hall regime. All our measurements are consistent with
quasiparticles of fractional charge e*. However, the results are also
consistent with particles of any charge (>= e*) as the system must rearrange
every time the flux enclosed increases by h/e.Comment: Postscript, 4 pages, gzipped (350 kB
Coulomb Charging Effects in an Open Quantum Dot
Low-temperature transport properties of a lateral quantum dot formed by
overlaying finger gates in a clean one-dimensional channel are investigated.
Continuous and periodic oscillations superimposed upon ballistic conductance
steps are observed, when the conductance G of the dot changes within a wide
range 0<G<6e^2/h. Calculations of the electrostatics confirm that the measured
periodic conductance oscillations correspond to successive change of the total
charge of the dot by . By modelling the transport it is shown that the
progression of the Coulomb oscillations into the region G>2e^2/h may be due to
suppression of inter-1D-subband scattering. Fully transmitted subbands
contribute to coherent background of conductance, while sequential tunneling
via weakly transmitted subbands leads to Coulomb charging of the dot.Comment: 12 pages, RevTeX, 15 eps figures included, submitted to Phys. Rev.
Experimental Evidence for Coulomb Charging Effects in an Open Quantum Dot at Zero Magnetic Field
We have measured the low-temperature transport properties of an open quantum
dot formed in a clean one-dimensional channel. For the first time, at zero
magnetic field, continuous and periodic oscillations superimposed upon
ballistic conductance steps are observed when the conductance through the dot
exceeds . We ascribe the observed conductance oscillations to
evidence for Coulomb charging effects in an open dot. This is supported by the
evolution of the oscillating features for as a function of both
temperature and barrier transparency. Our results strongly suggest that at zero
magnetic field, current theoretical and experimental understanding of Coulomb
charging effects overlooks charging in the presence of fully transmitted 1D
channels.Comment: To appear in Phys. Rev. Lett. 81 (Oct 19 issue
Energy-time entanglement of quasi-particles in solid-state devices
We present a proposal for the experimental observation of energy-time
entanglement of quasi-particles in mesoscopic physics. This type of
entanglement arises whenever correlated particles are produced at the same time
and this time is uncertain in the sense of quantum uncertainty, as has been
largely used in photonics. We discuss its feasibility for electron-hole pairs.
In particular, we argue that the recently fabricated 2DEG-2DHG junctions,
irradiated with a continuous laser, behave as "entanglers" for energy-time
entanglement.Comment: 4 pages, 3 figure
The physics and fabrication of low-dimensional hole systems
SIGLEAvailable from British Library Document Supply Centre-DSC:D064223 / BLDSC - British Library Document Supply CentreGBUnited Kingdo
Phase coherence, interference, and conductance quantization in a confined two-dimensional hole gas
A system of two parallel constrictions in a two-dimensional hole gas has been studied. At zero magnetic-field conductance quantization is observed through the individual constrictions. At high magnetic fields Aharonov-Bohm oscillations result from resonant tunneling through states encircling the repulsive potential between the constrictions. The oscillations demonstrate directly phase-coherent transport of holes