11,115 research outputs found
Coulomb Oscillations in Antidots in the Integer and Fractional Quantum Hall Regimes
We report measurements of resistance oscillations in micron-scale antidots in
both the integer and fractional quantum Hall regimes. In the integer regime, we
conclude that oscillations are of the Coulomb type from the scaling of magnetic
field period with the number of edges bound to the antidot. Based on both
gate-voltage and field periods, we find at filling factor {\nu} = 2 a tunneling
charge of e and two charged edges. Generalizing this picture to the fractional
regime, we find (again, based on field and gate-voltage periods) at {\nu} = 2/3
a tunneling charge of (2/3)e and a single charged edge.Comment: related papers at http://marcuslab.harvard.ed
Zero-Bias Anomalies in Narrow Tunnel Junctions in the Quantum Hall Regime
We report on the study of cleaved-edge-overgrown line junctions with a
serendipitously created narrow opening in an otherwise thin, precise line
barrier. Two sets of zero-bias anomalies are observed with an enhanced
conductance for filling factors and a strongly suppressed conductance
for . A transition between the two behaviors is found near . The zero-bias anomaly (ZBA) line shapes find explanation in
Luttinger liquid models of tunneling between quantum Hall edge states. The ZBA
for occurs from strong backscattering induced by suppression of
quasiparticle tunneling between the edge channels for the Landau
levels. The ZBA for arises from weak tunneling of quasiparticles
between the edge channels.Comment: version with edits for clarit
Cascade of Quantum Phase Transitions in Tunnel-Coupled Edge States
We report on the cascade of quantum phase transitions exhibited by
tunnel-coupled edge states across a quantum Hall line junction. We identify a
series of quantum critical points between successive strong and weak tunneling
regimes in the zero-bias conductance. Scaling analysis shows that the
conductance near the critical magnetic fields is a function of a single
scaling argument , where the exponent .
This puzzling resemblance to a quantum Hall-insulator transition points to
importance of interedge correlation between the coupled edge states.Comment: 4 pages, 3 figure
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