Current Distribution in the Quantum Hall Regime Observed in a Distributed Magnetic Field

1997 ◽  
Vol 66 (2) ◽  
pp. 413-418 ◽  
Author(s):  
Junichi Wakabayashi ◽  
Katsuhiko Sumiyoshi ◽  
Toshio Nagashima ◽  
Takashi Mochiku ◽  
Kazuo Kadowaki
1998 ◽  
Vol 249-251 ◽  
pp. 102-106 ◽  
Author(s):  
J. Wakabayashi ◽  
A. Tamagawa ◽  
T. Nagashima ◽  
T. Mochiku ◽  
K. Hirata

1999 ◽  
Vol 60 (4) ◽  
pp. 2561-2570 ◽  
Author(s):  
Rolf R. Gerhardts ◽  
Johannes Groß

2007 ◽  
Vol 21 (08n09) ◽  
pp. 1445-1449
Author(s):  
K. TAKEHANA ◽  
Y. IMANAKA ◽  
T. TAKAMASU ◽  
M. HENINI

We have investigated transport properties in high magnetic field of a gated two-dimensional electron system (2DES) separated by a thin barrier from a layer of self-assembled InAs quantum dots (QDs) in the quantum Hall regime. The quality of 2DES was found to be high enough to observe both integer and fractional quantum Hall effect (QHE), despite the proximity of the QD layer to the 2DES. However, significant suppression of the magnetoresistance (ρ xx ) and Hall resistance (ρ xy ) were observed in higher magnetic field range of filling factor ν < 1 when a positive voltage was applied to the front gate. The gate voltage dependence of ρ xx and ρ xy shows a well-defined hysteresis loop at the narrow gate voltage range between -0.2 and +0.2 V at ν < 1, while no anomaly was observed at ν > 1. We deduce that charging and discharging of QDs occurs when the gate voltage is varied around Vg ~ 0 V, which indicates that the electron charge states of the QDs affect the transport properties of the nearby 2DES only at ν < 1. We infer that the spin-flip process induces a non-equilibrium state in the 2DEG, which causes the suppression of ρ xx and ρ xy .


1996 ◽  
Vol 46 (S5) ◽  
pp. 2459-2460 ◽  
Author(s):  
A. M. C. Valkering ◽  
P. K. H. Sommerfeld ◽  
R. A. M. van de Ven ◽  
R. W. van der Heijden ◽  
F. A. P. Blom

2003 ◽  
Vol 15 (24) ◽  
pp. L377-L383 ◽  
Author(s):  
Alessandro Cresti ◽  
Riccardo Farchioni ◽  
Giuseppe Grosso ◽  
Giuseppe Pastori Parravicini

2009 ◽  
Vol 23 (12n13) ◽  
pp. 2616-2617
Author(s):  
GHISLAIN GRANGER ◽  
J. P. EISENSTEIN ◽  
J. L. RENO

We investigate the transport of heat in the integer quantized Hall regime. We make use of quantum point contacts (QPC's) positioned along the edge of a large quantum Hall droplet to both locally heat and locally detect temperature rises at the edge of the droplet. The detection scheme is thermoelectric, in essence identical to one introduced by Molenkamp, et al.1 in the early 1990's for heat transport experiments at zero magnetic field. At zero magnetic field we find that heat moves away from the heater QPC more or less isotropically. As expected from the Mott formula, we find a close connection between the detector QPC's thermoelectric response and the derivative, with respect to gate voltage, of its conductance. At high magnetic field our results show, not surprisingly, that heat transport is chiral in the quantum Hall regime. At total filling factor ν = 1 we inject a hot distribution of electrons into the edge with one of three QPC's. We observe a thermoelectric voltage at the other QPC's only if they are "downstream" from the heater. No signals are detected in the upstream direction. The magnitude of the detected thermal response is dependent upon the distance between the heater and detector QPC's. Additional measurements, in which a second QPC, between the heater and the detector, is used to drain away a portion of the injected heat, strongly suggest that the chiral heat transport we observe is indeed confined to the edge of the Hall droplet. Experiments are underway in the fractional quantum Hall regime to search for "upstream" heat propagation. Theory has suggested that such anti-chiral transport should exist at certain fractions, notably ν = 2/3, owing to backward-propagating neutral modes. Note from Publisher: This article contains the abstract only.


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