4 research outputs found
Current direction induced rectification effect on (integer) quantized Hall plateaus
Current polarization induced rectification of the quantized Hall plateaus
(QHPs) is studied within a Hartree type mean field approximation for
asymmetrically depleted samples. We first investigate the existence of the
current carrying incompressible strips (ISs), by solving the self-consistent
equations, and their influence on magneto-transport (MT) properties. Next, the
widths of the ISs are examined in terms of the steepness of the confining
potential profile considering gate defined Hall bars. The corresponding MT
coefficients are calculated using a local Ohm's law for a large fixed current
and are compared for symmetric and asymmetric depleted samples. We predict
that, the extend of the QHPs strongly depend on the current polarization, in
the out of linear response regime, when considering asymmetrically depleted
samples. Our results, concerning the extend of the QHPs depending on the
current polarization are in contrast to the ones of the conventional theories
of the integer quantized Hall effect (IQHE). We propose certain experimental
conditions to test our theoretical predictions at high mobility, narrow
samples.Comment: 4 pages, 3 figures, submitted to Phys. Re
Investigations on unconventional aspects in the quantum Hall regime of narrow gate defined channels
We report on theoretical and experimental investigations of the integer
quantized Hall effect in narrow channels at various mobilities. The Hall bars
are defined electrostatically in two-dimensional electron systems by biasing
metal gates on the surfaces of GaAs/AlGaAs heterostructures. In the low
mobility regime the classical Hall resistance line is proportional to the
magnetic field as measured in the high temperature limit and cuts through the
center of each Hall plateau. For high mobility samples we observe in linear
response measurements, that this symmetry is broken and the classical Hall line
cuts the plateaus not at the center but at higher magnetic fields near the
edges of the plateaus. These experimental results confirm the unconventional
predictions of a model for the quantum Hall effect taking into account mutual
screening of charge carriers within the Hall bar. The theory is based on
solving the Poisson and Schr\"odinger equations in a self-consistent manner.Comment: EP2DS-17 Proceedings, 6 Pages, 2 Figure
Interaction mediated asymmetries of the quantized Hall effect
Experimental and theoretical investigations on the integer quantized Hall
effect in gate defined narrow Hall bars are presented. At low electron mobility
the classical (high temperature) Hall resistance line RH(B) cuts through the
center of all Hall plateaus. In contrast, for our high mobility samples the
intersection point, at even filling factors \nu = 2; 4 ..., is clearly shifted
towards larger magnetic fields B. This asymmetry is in good agreement with
predictions of the screening theory, i. e. taking Coulomb interaction into
account. The observed effect is directly related to the formation of
incompressible strips in the Hall bar. The spin-split plateau at \nu= 1 is
found to be almost symmetric regardless of the mobility. We explain this within
the so-called effective g-model.Comment: 4 pages, 3 figure