scholarly journals Behaviour of topological defects of optical indicatrix orientation in cubic, hexagonal, trigonal and tetragonal crystals under conically distributed electric field. 2. The electric field and the optical beam parallel to the principal crystallographic directions

2015 ◽  
Vol 16 (1) ◽  
pp. 1 ◽  
Author(s):  
Yu Vasylkiv ◽  
T Kryvyy ◽  
I Skab ◽  
R Vlokh
Keyword(s):  
Electric Field ◽  
Topological Defects ◽  
Optical Beam ◽  
Optical Indicatrix ◽  
Tetragonal Crystals

HQC with the AC setup associated with topological defects

2011 ◽  
Vol 11 (5&6) ◽  
pp. 444-455
Author(s):  
Knut Bakke ◽  
Cláudio Furtado
Keyword(s):  
Dipole Moment ◽  
Electric Field ◽  
Magnetic Dipole ◽  
Magnetic Dipole Moment ◽  
Topological Defect ◽  
Dipole Moments ◽  
Topological Defects ◽  
Quantum Phases ◽  
Neutral Particles ◽  
New Formulation

In this work, we propose a new formulation allowing to realize the holonomic quantum computation with neutral particles with a permanent magnetic dipole moments interacting with an external electric field in the presence of a topological defect. We show that both the interaction of the electric field with the magnetic dipole moment and the presence of topological defect generate independent contributions to the geometric quantum phases which can be used to describe any arbitrary rotation on the magnetic dipole moment without using the adiabatic approximation.

scholarly journals Nematic topological defects positionally controlled by geometry and external fields

2018 ◽  
Vol 9 ◽  
pp. 109-118 ◽  
Author(s):  
Pavlo Kurioz ◽  
Marko Kralj ◽  
Bryce S Murray ◽  
Charles Rosenblatt ◽  
Samo Kralj
Keyword(s):  
Electric Field ◽  
Topological Charge ◽  
Order Parameter ◽  
Topological Defects ◽  
Two Dimensional ◽  
External Fields ◽  
Nematic Ordering ◽  
Spatial Positioning ◽  
A Charge ◽  
The Impact

Using a Landau–de Gennes approach, we study the impact of confinement topology, geometry and external fields on the spatial positioning of nematic topological defects (TDs). In quasi two-dimensional systems we demonstrate that a confinement-enforced total topological charge of m > 1/2 decays into elementary TDs bearing a charge of m = 1/2. These assemble close to the bounding substrate to enable essentially bulk-like uniform nematic ordering in the central part of a system. This effect is reminiscent of the Faraday cavity phenomenon in electrostatics. We observe that in certain confinement geometries, varying the correlation length size of the order parameter could trigger a global rotation of an assembly of TDs. Finally, we show that an external electric field could be used to drag the boojum fingertip towards the interior of the confinement cell. Assemblies of TDs could be exploited as traps for appropriate nanoparticles, opening several opportunities for the development of functional nanodevices.

LANDAU QUANTIZATION FOR A NEUTRAL PARTICLE IN THE PRESENCE OF TOPOLOGICAL DEFECTS

2012 ◽  
Vol 18 ◽  
pp. 101-104
Author(s):  
L. R. RIBEIRO ◽  
K. BAKKE ◽  
C. FURTADO
Keyword(s):  
Dipole Moment ◽  
Electric Field ◽  
Quantum Dynamics ◽  
Magnetic Dipole Moment ◽  
Short Communication ◽  
Neutral Particle ◽  
Topological Defect ◽  
Relativistic Quantum ◽  
Topological Defects ◽  
Landau Levels

In this short communication, we study the Landau levels in the non-relativistic quantum dynamics of a neutral particle which possesses a permanent magnetic dipole moment interacting with an external electric field in curved spacetime background with the presence or absence of a torsion field. We show that the presence of the topological defect breaks the infinite degeneracy of the Landau levels.

OBIC Analysis of Different Edge Terminations of Planar 1.6 kV 4H-SiC Diodes

2007 ◽  
Vol 556-557 ◽  
pp. 1007-1010 ◽  
Author(s):  
Christophe Raynaud ◽  
Daniel Loup ◽  
Phillippe Godignon ◽  
Raul Perez Rodriguez ◽  
Dominique Tournier ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Breakdown Voltage ◽  
High Voltage ◽  
Semiconductor Devices ◽  
Optical Beam ◽  
Induced Current ◽  
Bipolar Diodes ◽  
High Electric Fields ◽  
Optical Beam Induced Current

High voltage SiC semiconductor devices have been successfully fabricated and some of them are commercially available [1]. To achieve experimental breakdown voltage values as close as possible to the theoretical value, i.e. value of the theoretical semi-infinite diode, it is necessary to protect the periphery of the devices against premature breakdown due to locally high electric fields. Mesa structures and junction termination extension (JTE) as well as guard rings, and combinations of these techniques, have been successfully employed. Each of them has particular drawbacks. Especially, JTE are difficult to optimize in terms of impurity dose to implant, as well as in terms of geometric dimensions. This paper is a study of the spreading of the electric field at the edge of bipolar diodes protected by JTE and field rings, by optical beam induced current.

scholarly journals Near Breakdown Voltage Optical Beam Induced Current (OBIC) on 4H-SiC Bipolar Diode

2018 ◽  
Vol 924 ◽  
pp. 577-580 ◽  
Author(s):  
Dominique Planson ◽  
Besar Asllani ◽  
Hassan Hamad ◽  
Marie Laure Locatelli ◽  
Roxana Arvinte ◽  
...  
Keyword(s):  
Electric Field ◽  
Breakdown Voltage ◽  
Field Enhancement ◽  
Optical Beam ◽  
Induced Current ◽  
Electric Field Enhancement ◽  
Tcad Simulation ◽  
Optical Beam Induced Current

This paper presents OBIC measurements performed at near breakdown voltage on two devices with different JTE doses. Overcurrent has been measured either at the JTE periphery or at the P+ border. Such overcurrent is present due to the electric field enhancement near the breakdown voltage. This hypothesis is proved by the electroluminescence. TCAD simulation of two different JTE doses yielded similar results to the OBIC measurements.

scholarly journals Polarizability of electrically induced magnetic vortex “atoms”

2018 ◽  
Vol 185 ◽  
pp. 07003
Author(s):  
P.I. Karpov ◽  
S.I. Mukhin
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Domain Walls ◽  
Topological Defects ◽  
Magnetic Vortex ◽  
Distribution Profile ◽  
Magnetic Structures ◽  
Magnetic Vortices ◽  
Vortex Density ◽  
Magnetoelectric Materials

Electric field control of magnetic structures, particularly topological defects in magnetoelectric materials, draws a great attention, which has led to experimental success in creation and manipulation of single magnetic defects, such as skyrmions and domain walls. In this work we explore a scenario of electric field creation of another type of topological defects – magnetic vortices and antivortices. Because of interaction of magnetic and electric subsystems each magnetic vortex (antivortex) in magnetoelectric materials possesses quantized magnetic charge, responsible for interaction between vortices, and electric charge that couples them to electric field. This property of magnetic vortices makes possible their creation by electric fields. We show that the electric field, created by a cantilever tip, produces a “magnetic atom” with a localized spot of ordered vortices (“nucleus” of the atom) surrounded by antivortices (“electronic shells”). We analytically find the vortex density distribution profile and temperature dependence of polarizability of this structure and confirm it numerically by Monte Carlo simulation.

Ultrafast vector imaging of plasmonic skyrmion dynamics with deep subwavelength resolution

Science ◽  
2020 ◽  
Vol 368 (6489) ◽  
pp. eaba6415 ◽  
Author(s):  
Timothy J. Davis ◽  
David Janoschka ◽  
Pascal Dreher ◽  
Bettina Frank ◽  
Frank-J. Meyer zu Heringdorf ◽  
...  
Keyword(s):  
Electric Field ◽  
Surface Plasmons ◽  
Near Field ◽  
Topological Defects ◽  
Time Resolved ◽  
Time Dynamics ◽  
Continuous Vector Field ◽  
Dynamic Spin ◽  
Vector Structure ◽  
Momentum Coupling

Plasmonic skyrmions are an optical manifestation of topological defects in a continuous vector field. Identifying them requires characterization of the vector structure of the electromagnetic near field on thin metal films. Here we introduce time-resolved vector microscopy that creates movies of the electric field vectors of surface plasmons with subfemtosecond time steps and a 10-nanometer spatial scale. We image complete time sequences of propagating surface plasmons as well as plasmonic skyrmions, resolving all vector components of the electric field and their time dynamics, thus demonstrating dynamic spin-momentum coupling as well as the time-varying skyrmion number. The ability to image linear optical effects in the spin and phase structures of light in the single-nanometer range will allow for entirely novel microscopy and metrology applications.

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