Separately contacted edge states: A spectroscopic tool for the investigation of the quantum Hall effect

Würtz, A.; Wildfeuer, R.; Lorke, Axel; Deviatov, E. V.; Dolgopolov, V. T.

doi:10.1103/physrevb.65.075303

Cited by 59 publications

(133 citation statements)

References 29 publications

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“…Beyond that, we show in figure 5 that a distinct armchair edge current appears also in the regime of coherent electron focusing. This distinct armchair edge current in focusing experiments could be measured experimentally by means of an additional voltage probe placed on the stripe's edge or by contacting edge channels individually, as in [66,67].…”

Section: Edge Current Flowmentioning

confidence: 99%

Edge magnetotransport in graphene: A combined analytical and numerical study

Stegmann

Lorke

2015

Annalen der Physik

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The current flow along the boundary of graphene stripes in a perpendicular magnetic field is studied theoretically by the nonequilibrium Green's function method. In the case of specular reflections at the boundary, the Hall resistance shows equidistant peaks, which are due to classical cyclotron motion. When the strength of the magnetic field is increased, anomalous resistance oscillations are observed, similar to those found in a nonrelativistic 2D electron gas [New. J. Phys. 15:113047 (2013)]. Using a simplified model, which allows to solve the Dirac equation analytically, the oscillations are explained by the interference between the occupied edge states causing beatings in the Hall resistance. A rule of thumb is given for the experimental observability. Furthermore, the local current flow in graphene is affected significantly by the boundary geometry. A finite edge current flows on armchair edges, while the current on zigzag edges vanishes completely. The quantum Hall staircase can be observed in the case of diffusive boundary scattering. The number of spatially separated edge channels in the local current equals the number of occupied Landau levels. The edge channels in the local density of states are smeared out but can be made visible if only a subset of the carbon atoms is taken into account.

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Section: Edge Current Flowmentioning

confidence: 99%

Edge magnetotransport in graphene: A combined analytical and numerical study

Stegmann

Lorke

2015

Annalen der Physik

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“…The distinct hysteretic features suggest the relevance of very slow physical process in the enhancement and suppression of the inter-edge-channel scattering. The asymmetric features and the rapid reduction of R H in large current levels are interpreted as a consequence that the edge-confining potential is rearranged due to the electrostatic polarization of the edge channels 15,16) and irrelevant to the DNP. The effects of DNP on the inter-edge-channel scattering are more clearly demonstrated in the time traces of R H for I dc < 0 and I dc > 0 in Figs.…”

Section: 9)mentioning

confidence: 99%

Electron–Nuclear Spin Interaction in Edge States of Quantum Hall Systems

et al. 2003

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We have studied the electron-nuclear spin interaction in integer and fractional quantumHall edge channels. By selectively populating edge channels of different spin polarities, nuclear spins along the edge channels are dynamically polarized through the hyperfine interaction. The resultant dynamic nuclear polarization is detected with the edge-channel transport via nuclear magnetic resonance. The technique of controlling and detecting nuclear-spin polarization in quantum-Hall systems opens up new possibilities of developing nuclear-spin solid-state devices as well as shedding new light to spin properties of quantum-Hall systems. We demonstrate local controllability of the nuclear-spin polarization using a built-in micro-metal strip fabricated on a quantum-Hall device. We also demonstrate that the dynamic nuclear polarization can be utilized as a sensitive probe of the spin polarization of fractional quantum-Hall edge channels.

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“…This situation can not be achieved in usual experiments performed in the Hall-bar geometry 9 . In recent experiments in quasi-Corbino geometry 10,11 with direct biasing of the ES, no sign of ES crossing was observed, even when the ES imbalances exceeded the cyclotron gap 12 . This may be due to the fact that even at the crossing points, the electron spin flips, which are necessary for the inter-ES scattering, can be strongly suppressed 9 .…”

Section: Since Its Introduction By Halperinmentioning

confidence: 99%

“…The samples are patterned in a quasi-Corbino geometry 10 . Ohmic contacts are made to both electron layers simultaneously.…”

Section: Since Its Introduction By Halperinmentioning

confidence: 99%

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Topological defects in the edge-state structure in a bilayer electron system

et al. 2005

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We experimentally demonstrate, for the first time, formation of point-like topological defects in the edge state structure in the quantum Hall effect regime. By using of a selective population technique, we investigate equilibration processes between the edge states in bilayer electron structures with a high tunnelling rate between layers. Unexpected flattening of the I − V curves in perpendicular magnetic field at a specific filling factor combination and the recovery of the conventional nonlinear I − V characteristics in tilted fields give a strong evidence for the existence of topological defects.

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Separately contacted edge states: A spectroscopic tool for the investigation of the quantum Hall effect

Cited by 59 publications

References 29 publications

Edge magnetotransport in graphene: A combined analytical and numerical study

Edge magnetotransport in graphene: A combined analytical and numerical study

Electron–Nuclear Spin Interaction in Edge States of Quantum Hall Systems

Topological defects in the edge-state structure in a bilayer electron system

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