scholarly journals Compressibility of the two-dimensional electron gas: Measurements of the zero-field exchange energy and fractional quantum Hall gap

1994 ◽  
Vol 50 (3) ◽  
pp. 1760-1778 ◽  
Author(s):  
J. P. Eisenstein ◽  
L. N. Pfeiffer ◽  
K. W. West
2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Hailong Fu ◽  
Yijia Wu ◽  
Ruoxi Zhang ◽  
Jian Sun ◽  
Pujia Shan ◽  
...  

Abstract Even-denominator fractional quantum Hall (FQH) states, such as 5/2 and 7/2, have been well known in a two-dimensional electron gas (2DEG) for decades and are still investigated as candidates of non-Abelian statistics. In this paper, we present the observation of a 3/2 FQH plateau in a single-layer 2DEG with lateral confinement at a bulk filling factor of 5/3. The 3/2 FQH plateau is quantized at $$\left( {\frac{h}{{e^2}}} \right)/\left( {\frac{3}{2}} \right)$$ h e 2 ∕ 3 2 within 0.02%, and can survive up to 300 mK. This even-denominator FQH plateau may imply intriguing edge structure and excitation in FQH system with lateral confinement. The observations in this work demonstrate that understanding the effect of the lateral confinement on the many-body system is critical in the pursuit of important theoretical proposals involving edge physics, such as the demonstration of non-Abelian statistics and the realization of braiding for fault-tolerant quantum computation.


1987 ◽  
Vol 102 ◽  
Author(s):  
J. E. Cunningham ◽  
G. L Timp ◽  
E. F. Schubert ◽  
W. T. Tsang ◽  
P. G. N. DeVegvar ◽  
...  

ABSTRACTWe report our recent investigations of a new structure formed by b-doping the barrier of an AlGaAs/GaAs heterostructure. In this new structure we have observed both a mobility of 1.9×lO6cm2/Vsec and the fractional quantum hall effect. We compare low temperature mobilities and densities achieved with the δ-doped heterostructure with corresponding high values reported in the literature for the homogeneously- doped heterostructure. We show that systematic enhancements in both density and mobility occur in the b-doped heterostructure. By δ-doping both barriers of a quantum well we have also achieved electron concentrations of 4×1012cm -2 in the well.


2020 ◽  
Vol 11 (1) ◽  
pp. 17-35 ◽  
Author(s):  
Katherine A. Schreiber ◽  
Gábor A. Csáthy

Due to its extremely rich phase diagram, the two-dimensional electron gas exposed to perpendicular magnetic fields has been the subject of intense and sustained study. One particularly interesting problem in this system is that of the half-filled Landau level, where the Fermi sea of composite fermions, a fractional quantum Hall state arising from a pairing instability of the composite fermions, and the quantum Hall nematic were observed in the half-filled N = 0, N = 1, and N ≥ 2 Landau levels, respectively. Thus, different ground states developed in different half-filled Landau levels. This situation has recently changed, when evidence for both the paired fractional quantum Hall state and the quantum Hall nematic was reported in the half-filled N = 1 Landau level. Furthermore, a direct quantum phase transition between these two ordered states was found. These results highlight an intimate connection between pairing and nematicity, which is a topic of current interest in several strongly correlated systems, in a well-understood and low-disorder environment.


2004 ◽  
Vol 19 (9) ◽  
pp. 1153-1160 ◽  
Author(s):  
H van Zalinge ◽  
R W van der Heijden ◽  
J H Wolter ◽  
B Özyilmaz ◽  
A Böhm ◽  
...  

2000 ◽  
Vol 61 (16) ◽  
pp. 10910-10916 ◽  
Author(s):  
G. H. Kim ◽  
J. T. Nicholls ◽  
S. I. Khondaker ◽  
I. Farrer ◽  
D. A. Ritchie

1990 ◽  
Vol 64 (20) ◽  
pp. 2434-2437 ◽  
Author(s):  
W. Chen ◽  
M. Fritze ◽  
A. V. Nurmikko ◽  
D. Ackley ◽  
C. Colvard ◽  
...  

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