Spin- and valley-dependent commensurability oscillations and electric-field-induced quantum Hall plateaux in periodically modulated silicene

2014 ◽  
Vol 104 (21) ◽  
pp. 213109 ◽  
Author(s):  
Kh. Shakouri ◽  
P. Vasilopoulos ◽  
V. Vargiamidis ◽  
G.-Q. Hai ◽  
F. M. Peeters
Keyword(s):  
Electric Field ◽  
Quantum Hall ◽  
Commensurability Oscillations

Optical and electrical study of cap layer effect in QHE devices with double-2DEG

2013 ◽  
Vol 1617 ◽  
pp. 31-36 ◽  
Author(s):  
L. Zamora-Peredo ◽  
I. Cortes-Mestizo ◽  
L. García-Gonzáez ◽  
J. Hernández-Torres ◽  
T. Hernandez-Quiroz ◽  
...  
Keyword(s):  
Electric Field ◽  
Room Temperature ◽  
Quantum Hall ◽  
Three Samples ◽  
Cap Layer ◽  
Layer Effect ◽  
Hall Effect Measurements ◽  
Band Profile ◽  
Surface Electric Field ◽  
Dimensional Electron Gas

ABSTRACTIn this work we report on the characteristics of GaAs/AlGaAs heterostructures with a symmetric double two-dimensional electron gas (D-2DEG). Optical characterization was made by room temperature photoreflectance (PR) spectroscopy as well as electrical properties were determinated using the quantum Hall effect measurements at 2K. In order to study the surface effects on the conduction band profile, three samples with different GaAs cap layer thickness (25, 60 and 80 nm) were grown by the molecular beam epitaxy. Photoreflectance spectra at room temperature show the wide-period Franz-Keldysh oscillations between 1.42 and 1.70 eV originated by the surface electric field. The analysis of these oscillations shows that the surface electric field varies from 503 to 120 kV/cm whereas the thickness of the cap layer increases that was produced by the reduction of the depletion zone near the surface. Using QHE measurements we found that electron density increases if the surface electric field decreases.

Effect of finite electric field on the quantum Hall effect

1986 ◽  
Vol 170 (1-2) ◽  
pp. 202-208 ◽  
Author(s):  
T. Takamasu ◽  
S. Komiyama ◽  
S. Hiyamizu ◽  
S. Sasa
Keyword(s):  
Electric Field ◽  
Hall Effect ◽  
Quantum Hall Effect ◽  
Quantum Hall

scholarly journals Effect of Interactions on the Quantization of the Chiral Photocurrent for Double-Weyl Semimetals

2020 ◽  
Author(s):  
Ipsita Mandal
Keyword(s):  
Electric Field ◽  
Active Material ◽  
Quantum Hall ◽  
Polarized Light ◽  
Chiral Anomaly ◽  
Low Frequencies ◽  
Circularly Polarized Light ◽  
Ac Electric Field ◽  
Topological Semimetals ◽  
Dc Current

The circular photogalvanic effect (CPGE) is the photocurrent generated in an optically active material in response to an applied ac electric field, and it changes sign depending on the chirality of the incident circularly polarized light. It is a non-linear dc current as it is second-order in the applied electric field, and for a certain range of low frequencies, takes on a quantized value proportional to the topological charge for a system which is a source of nonzero Berry flux. We show that for a non-interacting double-Weyl node, the CPGE is proportional to two quanta of Berry flux. On examining the effect of short-ranged Hubbard interactions upto first-order corrections, we find that this quantization is destroyed. This implies that unlike the quantum Hall effect in gapped phases or the chiral anomaly in field theories, the quantization of the CPGE in topological semimetals is not protected.

scholarly journals Tunable fractional quantum Hall phases in bilayer graphene

Science ◽  
2014 ◽  
Vol 345 (6192) ◽  
pp. 61-64 ◽  
Author(s):  
Patrick Maher ◽  
Lei Wang ◽  
Yuanda Gao ◽  
Carlos Forsythe ◽  
Takashi Taniguchi ◽  
...  
Keyword(s):  
Symmetry Breaking ◽  
Electric Field ◽  
Degrees Of Freedom ◽  
Quantum Hall ◽  
Bilayer Graphene ◽  
Emergent Behavior ◽  
Topological Order ◽  
Fractional Quantum Hall ◽  
Model Platform ◽  
Quantizing Magnetic Field

Symmetry-breaking in a quantum system often leads to complex emergent behavior. In bilayer graphene (BLG), an electric field applied perpendicular to the basal plane breaks the inversion symmetry of the lattice, opening a band gap at the charge neutrality point. In a quantizing magnetic field, electron interactions can cause spontaneous symmetry-breaking within the spin and valley degrees of freedom, resulting in quantum Hall effect (QHE) states with complex order. Here, we report fractional QHE states in BLG that show phase transitions that can be tuned by a transverse electric field. This result provides a model platform with which to study the role of symmetry-breaking in emergent states with topological order.

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