The optical tweezer of skyrmions

Wang, Xi-Guang; Chotorlishvili, L.; Dugaev, V. K.; Ernst, A.; Maznichenko, I. V.; Arnold, N.; Jia, Chenglong; Berakdar, J.; Mertig, Ingrid; Barnaś, J.

doi:10.1038/s41524-020-00402-7

Cited by 28 publications

(12 citation statements)

References 60 publications

(40 reference statements)

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“…As many antiferromagnets are insulating, the optical manipulation of the magnetization in these materials is even more compelling. Recently, the optical trapping of skyrmions was demonstrated in spin-driven chiral multiferroics, where the coupling of an external electric field to the ferroelectric polarization due to the large intrinsic ME effect creates a DMI-like term, which allows the manipulation of skyrmions [27]. The same effect was exploited to coherently switch the polarity and chirality in a magnetic vortex by applying ultrashort electric field pulses [28].…”

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confidence: 99%

Dzyaloshinskii-Moriya interaction induced by an ultrashort electromagnetic pulse: Application to coherent (anti)ferromagnetic skyrmion nucleation

Desplat,

Meyer,

Bouaziz

et al. 2020

Preprint

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We show how a Dzyaloshinskii-Moriya interaction can be generated in an ultrathin metal film from the induced internal electric field created by an ultrashort electromagnetic pulse. This interaction does not require structural inversion-symmetry breaking, and its amplitude can be tuned depending on the amplitude of the field. We perform first-principles calculations to estimate the strength of the field-induced magnetoelectric coupling for ferromagnetic Fe, Co, and Ni, and antiferromagnetic Mn, as well as FePt alloys. Last, using atomistic simulations, we demonstrate how an isolated antiferromagnetic skyrmion can be coherently nucleated from the collinear background by an ultrashort pulse in electric field on a 100-fs timescale.

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confidence: 99%

Dzyaloshinskii-Moriya interaction induced by an ultrashort electromagnetic pulse: Application to coherent (anti)ferromagnetic skyrmion nucleation

Desplat,

Meyer,

Bouaziz

et al. 2020

Preprint

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“…In the case of superconducting vortices where the motion is overdamped, numerous methods to drive individual vortices, including nanotips 95,96 and optical trapping 97,98 , have been studied in experiments and simulations. Individual skyrmions can also be driven with different types of tips 99 , local magnetic field gradients 100,101 , and with optical trapping [102][103][104] . The method of driving individual particles though a background of other particles while measuring the drag on the driven particle from fluctuations is known as active rheology and has been studied experimentally and theoretically for colloidal particles [105][106][107][108][109] , granular matter [110][111][112] , active matter 113 , and superconducting vortex systems 91,96,114,115 .…”

Section: Introductionmentioning

confidence: 99%

Commensuration Effects on Skyrmion Hall Angle and Drag for Manipulation of Skyrmions on Two-Dimensional Periodic Substrates

Reichhardt,

Reichhardt

2022

Preprint

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We examine the dynamics of an individually driven skyrmion moving through a background lattice of skyrmions coupled to a 2D periodic substrate as we vary the ratio of the number of skyrmions to the number of pinning sites across commensurate and incommensurate conditions. As the skyrmion density increases, the skyrmion Hall angle is nonmonotonic, dropping to low or zero values in commensurate states and rising to an enhanced value in incommensurate states. Under commensuration, the driven skyrmion is channeled by a symmetry direction of the pinning array and exhibits an increased velocity. At fillings for which the skyrmion Hall angle is zero, the velocity has a narrow band noise signature, while for incommensurate fillings, the skyrmion motion is disordered and the velocity noise is broad band. Under commensurate conditions, multi-step depinning transitions appear and the skyrmion Hall angle is zero at low drives but becomes finite at higher drives, while at incommensurate fillings there is only a single depinning transition. As the gyrotropic component of the skyrmion dynamics, called the Magnus force, increases, peaks in the velocity that appear in commensurate regimes cross over to dips, and new types of directional locking effects can arise in which the skyrmion travels along other symmetry directions of the background lattice. At large Magnus forces, and particularly at commensurate fillings, the driven skyrmion can experience a velocity boost in which the skyrmion moves faster than the applied drive due to the alignment of the Magnus-induced velocity with the driving direction. In some cases, an increase of the Magnus force can produce regimes of enhanced pinning when the skyrmion is forced to move along a non-symmetry direction of the periodic pinning array. This is in contrast to systems with random pinning, where increasing the Magnus force generally reduces the pinning effect. We demonstrate these dynamics for both square and triangular substrates, and map out the different regimes as a function of filling fraction, pinning force, and the strength of the Magnus force in a series of dynamic phase diagrams.

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“…In experiments on skyrmion systems, aspects of the pinning landscape have been examined by moving individual skyrmions with local tips [39,40]. It is also possible to drag individual skyrmions with optical traps [41] or by other means [42] and to examine the motion of the skyrmions within the traps as well as changes in the velocity and skyrmion Hall angle as a function of driving force. Most of the extensive numerical and experimental studies of the dynamics of individually dragged particles have focused on bulk properties such as the average velocity or effective drag coefficients, and there is little work examining how the time series, noise fluctuations, or depinning threshold of a single probe particle would change when quenched disorder is present.…”

Section: Introductionmentioning

confidence: 99%

Fluctuations and Pinning for Individually Manipulated Skyrmions

Reichhardt

2021

Front. Phys.

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We numerically examine the dynamics of individually dragged skyrmions interacting simultaneously with an array of other skyrmions and quenched disorder. For drives just above depinning, we observe a broadband noise signal with a 1/f characteristic, while at higher drives, narrowband or white noise appears. Even in the absence of quenched disorder, the threshold force that must be applied to translate the driven skyrmion is finite due to elastic interactions with other skyrmions. The depinning threshold increases as the strength of the quenched disorder is raised. Above the depinning force, the skyrmion moves faster in the presence of quenched disorder than in a disorder-free system since the pinning sites prevent other skyrmions from being dragged along with the driven skyrmion. For strong pinning, we find a stick-slip motion of the driven skyrmion which produces a telegraph noise signature. The depinning threshold increases monotonically with skyrmion density in the absence of quenched disorder, but when pinning is present, the depinning threshold changes nonmonotonically with skyrmion density, and there are reentrant pinned phases due to a competition between pinning induced by the quenched disorder and that produced by the elastic interactions of the skyrmion lattice.

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The optical tweezer of skyrmions

Cited by 28 publications

References 60 publications

Dzyaloshinskii-Moriya interaction induced by an ultrashort electromagnetic pulse: Application to coherent (anti)ferromagnetic skyrmion nucleation

Dzyaloshinskii-Moriya interaction induced by an ultrashort electromagnetic pulse: Application to coherent (anti)ferromagnetic skyrmion nucleation

Commensuration Effects on Skyrmion Hall Angle and Drag for Manipulation of Skyrmions on Two-Dimensional Periodic Substrates

Fluctuations and Pinning for Individually Manipulated Skyrmions

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