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Posted On: 03/11/2017 7:56:14 AM
Post# of 22463
Re: Puravida19 #5480
Dynamics and inertia of a skyrmion in chiral magnets: a linear response approach based on magnon excitations
Shi-Zeng Lin
(Submitted on 9 Mar 2017)
Taking all the magnon modes into account, we derive the skyrmion dynamics in response to a weak external drive. A skyrmion is centrosymmetric and the magnon modes can be characterized by an angular momentum. For a weak distortion of a skyrmion, only the magnon modes with an angular momentum
|m|=1
govern the dynamics of skyrmion topological center. The skyrmion inertia is determined by the magnon modes in the continuum spectrum. For a skyrmion driven by a magnetic field gradient or by a spin transfer torque generated by a current, the dynamical response is practically instantaneous. This justifies the rigid skyrmion approximation used in the Thiele's collective coordinate approach. For a skyrmion driven by a spin Hall torque, the torque couples to the skyrmion motion through the magnons in the continuum and damping, therefore the skyrmion dynamics shows a sizable inertia in this case. The trajectory of a skyrmion is an ellipse for an ac drive of spin Hall torque.
https://arxiv.org/abs/1703.03099
VVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVV
https://en.wikipedia.org/wiki/Centrosymmetry
In crystallography, a point group which contains an inversion center as one of its symmetry elements is centrosymmetric.[1] In such a point group, for every point (x, y, z) in the unit cell there is an indistinguishable point (-x, -y, -z). Such point groups are also said to have inversion symmetry.[2] Point reflection is a similar term used in geometry. Crystals with an inversion center cannot display certain properties, such as the piezoelectric effect.
Shi-Zeng Lin
(Submitted on 9 Mar 2017)
Taking all the magnon modes into account, we derive the skyrmion dynamics in response to a weak external drive. A skyrmion is centrosymmetric and the magnon modes can be characterized by an angular momentum. For a weak distortion of a skyrmion, only the magnon modes with an angular momentum
|m|=1
govern the dynamics of skyrmion topological center. The skyrmion inertia is determined by the magnon modes in the continuum spectrum. For a skyrmion driven by a magnetic field gradient or by a spin transfer torque generated by a current, the dynamical response is practically instantaneous. This justifies the rigid skyrmion approximation used in the Thiele's collective coordinate approach. For a skyrmion driven by a spin Hall torque, the torque couples to the skyrmion motion through the magnons in the continuum and damping, therefore the skyrmion dynamics shows a sizable inertia in this case. The trajectory of a skyrmion is an ellipse for an ac drive of spin Hall torque.
https://arxiv.org/abs/1703.03099
VVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVV
https://en.wikipedia.org/wiki/Centrosymmetry
In crystallography, a point group which contains an inversion center as one of its symmetry elements is centrosymmetric.[1] In such a point group, for every point (x, y, z) in the unit cell there is an indistinguishable point (-x, -y, -z). Such point groups are also said to have inversion symmetry.[2] Point reflection is a similar term used in geometry. Crystals with an inversion center cannot display certain properties, such as the piezoelectric effect.
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