Bound states induced giant oscillations of the conductance in the quantum Hall regime

Abstract

We theoretically studied the quasiparticle transport in a 2D electron gas biased in the quantum Hall regime and in the presence of a lateral potential barrier. The lateral junction hosts the specific magnetic field dependent quasiparticle states highly localized in the transverse direction. The quantum tunnelling across the barrier provides a complex bands structure of a one-dimensional energy spectrum of these bound states, [Formula: see text], where p y is the electron momentum in the longitudinal direction y. Such a spectrum manifests itself by a large number of peaks and drops in the dependence of the magnetic edge states transmission coefficient D(E ) on the electron energy E. E.g. the high value of D occurs as soon as the electron energy E reaches gaps in the spectrum. These peaks and drops of D(E) result in giant oscillations of the transverse conductance G x with the magnetic field and/or the transport voltage. Our theoretical analysis, based on the coherent macroscopic quantum superposition of the bound states and the magnetic edge states propagating along the system boundaries, is in a good accord with the experimental observations found in Kang et al (2000 Lett. Nat. 403 59).

Giant oscillations of the current in a dirty 2D electron system flowing perpendicular to a lateral barrier under magnetic field

“…Dynamics and kinetics of electrons in 2DEG in the presence of a lateral barrier under magnetic field H was experimentally and theoretically investigated in the situation that the current flows along 9,10 and perpendicular 8,19 to the barrier in ballistic samples. In all these cases giant conductance oscillations have been shown to arise.…”

“…The object of the present paper is to investigate transport properties of a dirty biased 2DEG with a lateral barrier under semiclassical magnetic field, the barrier being placed perpendicular to the current. In contrast to the ballistic situation considered in paper 19 the contribution of the conventional edge states to the conductance is neglected assuming the following inequalities being satisfied: ω H τ ≫ 1; L y ≫ l 0 (ω H τ ) where ω H = eH/mc and l 0 = v F τ are the cyclotron frequency and the electron free path length, respectively, while τ is the free path time and v F is the Fermi velocity. It is shown that the above-mentioned bands and gaps manifest themselves by giant oscillations of the transverse conductance with a change of the magnetic field of the gate voltage.…”