Tunneling spectroscopy of Landau band gaps at a quantum Hall line junction with adjustable Fermi level

Habl, M.; Reinwald, Matthias; Wegscheider, Werner; Bichler, Max; Abstreiter, G.

doi:10.1103/physrevb.73.205305

Cited by 5 publications

(8 citation statements)

References 19 publications

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“…For weakly coupled electron systems, Ho has calculated the energy dispersion by using an approximation approach [7]. Though the result reflects the actual dispersion very well, the gap positions differ noticeably from the findings of a complete quantum mechanical calculation if a fine energy resolution is relevant as for our experiment [11,12]. Instead of combining the dispersions of both subsystems, Takagaki and Ploog have developed a tight-binding model which is not only applicable for weakly, but also for strongly coupled electron systems [13].…”

Section: Introductionmentioning

confidence: 60%

“…For a decreasing temperature or a rising magnetic field, an increasing number of different interference paths affects the conductance. However, the B-dependence cannot be investigated as the observed AB oscillations are restricted to just one conductance peak [10,11].…”

Section: Tunneling Modelsmentioning

confidence: 99%

“…Within a real barrier, however, there exist imperfections which lead to a local enhancement of the tunneling probability. These tunneling centers, which are considered in the model of Kim and Fradkin [9], give rise to Aharonov-Bohm (AB) interferences between the opposite edge channels along the barrier [10,11]. In addition, the point contacts are responsible for conductance fluctuations observed at low magnetic fields [12].…”

Section: Aharonov-bohm Effectmentioning

confidence: 99%

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Laterally coupled and field‐induced quantum Hall systems

Habl

Wegscheider

2008

Physica Status Solidi (b)

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A quantum Hall system which is divided into two laterally coupled subsystems by means of a tunneling barrier exhibits a complex Landau level dispersion. Magnetotunneling spectroscopy is employed to investigate the small energy gaps which separate subsequent Landau bands. The control on the Fermi level permits to trace the anticrossings for varying magnetic fields. The band structure calculation predicts a magnetic shift of the band gaps on the scale of the cyclotron energy. This effect is confirmed experimentally by a displacement of the conductance peaks on the axis of the filling factor. Tunneling centers within the barrier are responsible for quantum interferences between opposite edge channels. Due to the disorder potential, the corresponding Aharonov-Bohm interferometers generate additional long-period and irregular conductance features. In the regime of strong localization, conductance fluctuations occur at small magnetic fields before the onset of the regular Landau oscillations. The Landau dispersion is obtained by a dedicated algorithm which solves the Schrödinger equation exactly for a single electron residing in a quantum Hall system with an arbitrary unidirectional, threefold staircase potential.

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Section: Introductionmentioning

confidence: 60%

Section: Tunneling Modelsmentioning

confidence: 99%

Section: Aharonov-bohm Effectmentioning

confidence: 99%

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Laterally coupled and field‐induced quantum Hall systems

Habl

Wegscheider

2008

Physica Status Solidi (b)

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“…This is in contrast to planar barrier systems, for example the planar antiwire of Refs. [10,11], where the coupling decreases exponentially at high B. The strong anticrossings result in both positive curvatures, corresponding to an electron-like mass, and negative curvatures, representing a hole-like mass, in various parts of the dispersion.…”

Section: Hartree Simulation At Large Bmentioning

confidence: 99%

Hartree simulations of coupled quantum Hall edge states in corner-overgrown heterostructures

et al. 2013

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The electronic states in a corner-overgrown bent GaAs/AlGaAs quantum well heterostructure are studied with numerical Hartree simulations. Transmission electron microscope pictures of the junction sharpness are shown to justify the sharp-corner potential assumed for these calculations. In a tilted magnetic field, both facets of the bent quantum well are brought to a quantum Hall (QH) state, and the corner hosts an unconventional hybrid system of coupled counter-propagating quantum Hall edges and an additional 1D accumulation wire. We show how, in contrast to coplanar barrier-junctions of QH systems, the coupling between the three subsystems increases as a function of the applied magnetic field, and discuss the implications of the numerical results for the interpretation of experimental data on bent quantum Hall systems reported elsewhere.

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“…The parabolic cylinder functions have important applications in theoretical physics. In fact, the wave functions of many quantum systems are represented by the parabolic cylinder functions [32][33][34][35]. In this paper we construct the Barut-Girardello coherent states for the parabolic cylinder functions.…”

Section: Introductionmentioning

confidence: 99%