scholarly journals Upstream modes and antidots poison graphene quantum Hall effect

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
N. Moreau ◽  
B. Brun ◽  
S. Somanchi ◽  
K. Watanabe ◽  
T. Taniguchi ◽  
...  
Keyword(s):  
Hall Effect ◽  
Quantum Hall Effect ◽  
Quantum Hall ◽  
High Mobility ◽  
Charge Carriers ◽  
Remarkable Property ◽  
One Dimensional ◽  
Quantum Hall Regime ◽  
Hall Regime ◽  
Scanning Gate

AbstractThe quantum Hall effect is the seminal example of topological protection, as charge carriers are transmitted through one-dimensional edge channels where backscattering is prohibited. Graphene has made its marks as an exceptional platform to reveal new facets of this remarkable property. However, in conventional Hall bar geometries, topological protection of graphene edge channels is found regrettably less robust than in high mobility semi-conductors. Here, we explore graphene quantum Hall regime at the local scale, using a scanning gate microscope. We reveal the detrimental influence of antidots along the graphene edges, mediating backscattering towards upstream edge channels, hence triggering topological breakdown. Combined with simulations, our experimental results provide further insights into graphene quantum Hall channels vulnerability. In turn, this may ease future developments towards precise manipulation of topologically protected edge channels hosted in various types of two-dimensional crystals.

scholarly journals Counter-propagating charge transport in the quantum Hall effect regime

Science ◽  
2019 ◽  
Vol 363 (6422) ◽  
pp. 54-57 ◽  
Author(s):  
Fabien Lafont ◽  
Amir Rosenblatt ◽  
Moty Heiblum ◽  
Vladimir Umansky
Keyword(s):  
Hall Effect ◽  
Quantum Hall Effect ◽  
Electron Gas ◽  
Quantum Hall ◽  
Charge Carriers ◽  
Perpendicular Magnetic Field ◽  
Quantum Hall Regime ◽  
Hall Regime ◽  
Spin Polarized ◽  
Conjugate States

The quantum Hall effect, observed in a two-dimensional (2D) electron gas subjected to a perpendicular magnetic field, imposes a 1D-like chiral, downstream, transport of charge carriers along the sample edges. Although this picture remains valid for electrons and Laughlin’s fractional quasiparticles, it no longer holds for quasiparticles in the so-called hole-conjugate states. These states are expected, when disorder and interactions are weak, to harbor upstream charge modes. However, so far, charge currents were observed to flow exclusively downstream in the quantum Hall regime. Studying the canonical spin-polarized and spin-unpolarized v = 2/3 hole-like states in GaAs-AlGaAs heterostructures, we observed a significant upstream charge current at short propagation distances in the spin unpolarized state.

scholarly journals FIELD THEORY OF ANISOTROPIC QUANTUM HALL GAS: METROLOGY AND A NOVEL QUANTUM HALL REGIME

2003 ◽  
Vol 17 (27) ◽  
pp. 4765-4818 ◽  
Author(s):  
K. ISHIKAWA ◽  
T. AOYAMA ◽  
Y. ISHIZUKA ◽  
N. MAEDA
Keyword(s):  
Hall Effect ◽  
Quantum Hall Effect ◽  
Quantum Hall ◽  
Hall Conductance ◽  
Von Neumann ◽  
Integer Quantum Hall Effect ◽  
Quantum Hall Regime ◽  
Realistic Situation ◽  
Hall Regime ◽  
Integer Quantum

The von Neumann lattice representation is a convenient representation for studying several intriguing physics of quantum Hall systems. In this formalism, electrons are mapped to lattice fermions. A topological invariant expression of the Hall conductance is derived and is used for the proof of the integer quantum Hall effect in the realistic situation. Anisotropic quantum Hall gas is investigated based on the Hartree–Fock approximation in the same formalism. Thermodynamic properties, transport properties, and unusual response under external modulations are found. Implications for the integer quantum Hall effect in the finite systems are also studied and a new quantum Hall regime with non-zero longitudinal resistance is shown to exist.

scholarly journals Half integer quantum Hall effect in high mobility single layer epitaxial graphene

2009 ◽  
Vol 95 (22) ◽  
pp. 223108 ◽  
Author(s):  
Xiaosong Wu ◽  
Yike Hu ◽  
Ming Ruan ◽  
Nerasoa K Madiomanana ◽  
John Hankinson ◽  
...  
Keyword(s):  
Hall Effect ◽  
Quantum Hall Effect ◽  
Quantum Hall ◽  
High Mobility ◽  
Single Layer ◽  
Epitaxial Graphene ◽  
Half Integer ◽  
Integer Quantum Hall Effect ◽  
Integer Quantum

scholarly journals Quantum Hall effect in a bulk antiferromagnet EuMnBi2 with magnetically confined two-dimensional Dirac fermions

2016 ◽  
Vol 2 (1) ◽  
pp. e1501117 ◽  
Author(s):  
Hidetoshi Masuda ◽  
Hideaki Sakai ◽  
Masashi Tokunaga ◽  
Yuichi Yamasaki ◽  
Atsushi Miyake ◽  
...  
Keyword(s):  
Hall Effect ◽  
Quantum Hall Effect ◽  
Magnetic Order ◽  
Quantum Hall ◽  
High Mobility ◽  
Interlayer Coupling ◽  
Dirac Fermions ◽  
Energy Excitation ◽  
Integer Quantum Hall Effect ◽  
Dirac Materials

For the innovation of spintronic technologies, Dirac materials, in which low-energy excitation is described as relativistic Dirac fermions, are one of the most promising systems because of the fascinating magnetotransport associated with extremely high mobility. To incorporate Dirac fermions into spintronic applications, their quantum transport phenomena are desired to be manipulated to a large extent by magnetic order in a solid. We report a bulk half-integer quantum Hall effect in a layered antiferromagnet EuMnBi2, in which field-controllable Eu magnetic order significantly suppresses the interlayer coupling between the Bi layers with Dirac fermions. In addition to the high mobility of more than 10,000 cm2/V s, Landau level splittings presumably due to the lifting of spin and valley degeneracy are noticeable even in a bulk magnet. These results will pave a route to the engineering of magnetically functionalized Dirac materials.

THE QUANTUM HALL EFFECT IN QUASI-ONE-DIMENSIONAL ORGANIC CONDUCTORS

2002 ◽  
Vol 16 (20n22) ◽  
pp. 3089-3089
Author(s):  
V. M. YAKOVENKO
Keyword(s):  
Hall Effect ◽  
Quantum Hall Effect ◽  
Quantum Hall ◽  
Organic Conductors ◽  
Temperature Evolution ◽  
Edge States ◽  
One Dimensional ◽  
Recent Developments ◽  
Theoretical Overview

Theoretical overview of the quantum Hall effect in quasi-one-dimensional (Q1D) organic conductors (TMTSF) 2 X will be presented.1 The emphasis will be on the recent developments, such as the temperature evolution of the Hall effect2,3 and the chiral edge states.4 Time permitting, a theory of the nonchiral electron edge states in a Q1D triplet superconductor5 and the holon edge states in the charge-gap regime6 will be presented too.

Quantum Hall effect transition in scanning gate experiments

2007 ◽  
Vol 76 (8) ◽  
Author(s):  
A. Baumgartner ◽  
T. Ihn ◽  
K. Ensslin ◽  
K. Maranowski ◽  
A. C. Gossard
Keyword(s):  
Hall Effect ◽  
Quantum Hall Effect ◽  
Quantum Hall ◽  
Scanning Gate

The fractional quantum Hall effect in high mobility two-dimensional hole gases

1992 ◽  
Vol 263 (1-3) ◽  
pp. 81-86 ◽  
Author(s):  
A.G. Davies ◽  
R. Newbury ◽  
M. Pepper ◽  
J.E.F. Frost ◽  
D.A. Ritchie ◽  
...  
Keyword(s):  
Hall Effect ◽  
Quantum Hall Effect ◽  
Quantum Hall ◽  
High Mobility ◽  
Fractional Quantum Hall Effect ◽  
Two Dimensional ◽  
Fractional Quantum ◽  
Fractional Quantum Hall
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