scholarly journals Spins, charges, and currents at domain walls in a quantum Hall Ising ferromagnet

2002 ◽  
Vol 66 (4) ◽  
Author(s):  
L. Brey ◽  
C. Tejedor
Keyword(s):  
Domain Walls ◽  
Quantum Hall ◽  
Ising Ferromagnet

scholarly journals Controllable quantum point junction on the surface of an antiferromagnetic topological insulator

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Nicodemos Varnava ◽  
Justin H. Wilson ◽  
J. H. Pixley ◽  
David Vanderbilt
Keyword(s):  
Topological Insulator ◽  
Information Science ◽  
Domain Walls ◽  
Quantum Hall ◽  
Edge State ◽  
Wave Functions ◽  
Quantum Hall Systems ◽  
Electron Quantum ◽  
Quantum Point ◽  
Higher Temperature

AbstractEngineering and manipulation of unidirectional channels has been achieved in quantum Hall systems, leading to the construction of electron interferometers and proposals for low-power electronics and quantum information science applications. However, to fully control the mixing and interference of edge-state wave functions, one needs stable and tunable junctions. Encouraged by recent material candidates, here we propose to achieve this using an antiferromagnetic topological insulator that supports two distinct types of gapless unidirectional channels, one from antiferromagnetic domain walls and the other from single-height steps. Their distinct geometric nature allows them to intersect robustly to form quantum point junctions, which then enables their control by magnetic and electrostatic local probes. We show how the existence of stable and tunable junctions, the intrinsic magnetism and the potential for higher-temperature performance make antiferromagnetic topological insulators a promising platform for electron quantum optics and microelectronic applications.

scholarly journals Nanoscale strain engineering of giant pseudo-magnetic fields, valley polarization, and topological channels in graphene

2020 ◽  
Vol 6 (19) ◽  
pp. eaat9488 ◽  
Author(s):  
C.-C. Hsu ◽  
M. L. Teague ◽  
J.-Q. Wang ◽  
N.-C. Yeh
Keyword(s):  
Magnetic Fields ◽  
Domain Walls ◽  
Quantum Hall ◽  
Strain Engineering ◽  
Scanning Tunneling ◽  
Monolayer Graphene ◽  
Tunneling Microscopy ◽  
One Dimensional ◽  
Valley Polarization ◽  
Topological States

The existence of nontrivial Berry phases associated with two inequivalent valleys in graphene provides interesting opportunities for investigating the valley-projected topological states. Examples of such studies include observation of anomalous quantum Hall effect in monolayer graphene, demonstration of topological zero modes in “molecular graphene” assembled by scanning tunneling microscopy, and detection of topological valley transport either in graphene superlattices or at bilayer graphene domain walls. However, all aforementioned experiments involved nonscalable approaches of either mechanically exfoliated flakes or atom-by-atom constructions. Here, we report an approach to manipulating the topological states in monolayer graphene via nanoscale strain engineering at room temperature. By placing strain-free monolayer graphene on architected nanostructures to induce global inversion symmetry breaking, we demonstrate the development of giant pseudo-magnetic fields (up to ~800 T), valley polarization, and periodic one-dimensional topological channels for protected propagation of chiral modes in strained graphene, thus paving a pathway toward scalable graphene-based valleytronics.

scholarly journals Charge and spin textures of Ising quantum Hall ferromagnet domain walls

2019 ◽  
Vol 100 (23) ◽  
Author(s):  
Jeroen Danon ◽  
Ajit C. Balram ◽  
Samuel Sánchez ◽  
Mark S. Rudner
Keyword(s):  
Domain Walls ◽  
Quantum Hall

scholarly journals Microscopic theory of a quantum Hall Ising nematic: Domain walls and disorder

2013 ◽  
Vol 88 (4) ◽  
Author(s):  
Akshay Kumar ◽  
S. A. Parameswaran ◽  
S. L. Sondhi
Keyword(s):  
Domain Walls ◽  
Quantum Hall ◽  
Microscopic Theory

ON THE CURRENT DOMAIN PICTURE OF THE MICROWAVE INDUCED ZERO-RESISTANCE OF HIGH MOBILITY QUANTUM HALL SYSTEMS

2004 ◽  
Vol 18 (27n29) ◽  
pp. 3489-3492 ◽  
Author(s):  
MANFRED OSWALD ◽  
JOSEF OSWALD
Keyword(s):  
Domain Walls ◽  
Quantum Hall ◽  
High Mobility ◽  
Hall Resistance ◽  
Quantum Hall Systems ◽  
Current Path ◽  
Zero Resistance ◽  
Longitudinal Resistance ◽  
Resistance State ◽  
Current Filaments

Numerical simulations of the current domain picture, which is frequently used to describe the microwave induced zero resistance state of high mobility 2-dimensional electron systems, are shown. We demonstrate, that we obtain a situation, which is equivalent to the current domain picture by introducing an artificial domain wall into our network model for magneto transport. However, in contrast to the current domain picture the current in our simulations is insensitive to the width of the domains. Finally we propose an alternative picture where we use several domain walls, which are distributed along the current path. These serve as current filaments and lead also to a vanishing longitudinal resistance, while the Hall resistance remains unchanged.

scholarly journals MAXWELL-CHERN-SIMONS ELECTRODYNAMICS ON A DISK

1994 ◽  
Vol 09 (19) ◽  
pp. 3417-3441 ◽  
Author(s):  
A.P. BALACHANDRAN ◽  
L. CHANDAR ◽  
E. ERCOLESSI ◽  
T.R. GOVINDARAJAN ◽  
R. SHANKAR
Keyword(s):  
Quantum Hall Effect ◽  
Lie Group ◽  
Single Particle ◽  
Domain Walls ◽  
Quantum Hall ◽  
The Novel ◽  
Edge States ◽  
Zero Energy ◽  
Maxwell Theory ◽  
Chern Simons

The Maxwell-Chern-Simons (MCS) Lagrangian is the Maxwell Lagrangian augmented by the Chern-Simons term. In this paper, we study the MCS and Maxwell Lagrangians on a disk D. They are of interest for the quantum Hall effect, and also when the disk and its exterior are composed of different media. We show that quantization is not unique, but depends on a nonnegative parameter λ. 1/λ is the penetration depth of the fields described by these Lagrangians into the medium in the exterior of D. For λ=0, there are edge observables and edge states localized at the boundary ∂D for the MCS system. They describe the affine Lie group [Formula: see text]. Their excitations carry zero energy, signifying an infinite degeneracy of all states of the theory. There is also an additional infinity of single particle excitations of exactly the same energy proportional to |k|, k being the strength of the Chern-Simons term. The MCS theory for λ=0 has the huge symmetry group [Formula: see text]. In the Maxwell theory, the last-mentioned excitations are absent while the edge observables, which exist for λ=0, commute. Also, these excitations are described by states which are not localized at ∂D and are characterized by a continuous and infinitely degenerate spectrum. All these degeneracies are lifted and edge observables and their states cease to exist for λ>0. The novel excitations discovered in this paper should be accessible to observations. We will discuss issues related to observations, as also the generalization of the present considerations to vortices, domain walls and monopoles, in a paper under preparation.

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