SciPost Submission Page
Interaction and collision of skyrmions in chiral antiferromagnets
by George Theodorou, Stavros Komineas
Submission summary
| Authors (as registered SciPost users): | Stavros Komineas |
| Submission information | |
|---|---|
| Preprint Link: | https://arxiv.org/abs/2305.13515v1 (pdf) |
| Date submitted: | 2023-05-24 07:13 |
| Submitted by: | Komineas, Stavros |
| Submitted to: | SciPost Physics |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approaches: | Theoretical, Computational |
Abstract
Skyrmions in an antiferromagnet can travel as solitary waves in stark contrast to the situation in ferromagnets. Traveling skyrmion solutions have been found numerically in chiral antiferromagnets. We consider head-on collision events between two skyrmions. We find that the result of the collision depends on the initial velocity of the skyrmions. For small velocities, the skyrmions are shrinking as they are approaching, they bounce back and eventually acquire almost their initial speed. For larger velocities, the skyrmions approach each other and shrink until they become singular points and are eventually annihilated. We describe the observed phenomena in terms of skyrmion energetics and thus determine the regimes of the different dynamical behaviors.
Current status:
Reports on this Submission
Report 2 by Elizaveta Tremsina on 2024-5-23 (Invited Report)
Strengths
1. Work is well presented
2. Model and method clearly presented
3. Interesting collision cases presented
Weaknesses
1. Missing key references to past work in introduction, especially regarding chiral skyrmion dynamics.
10.1103/PhysRevLett.116.147203
10.1103/PhysRevB.106.L220402
10.1126/SCIENCE.ADD5751
2. No mention of skyrmion mass or inertia, perhaps this is relevant point to consider when talking about energetics of collisions.
10.1103/PhysRevB.106.144405
3. The effective field approach provided in section 3 seems like a nice simple model but it is unclear how it is actually used in the simulations to make sense of the collisions or predict their various outcomes. Thus, it is difficult to objectively judge the validity and usefulness of that portion of the work.
Additionally, perhaps it would be useful to tie in past work on skyrmion-skyrmion interactions, in which the potential function was derived analytically, and see how it relates to the field analytics of section 3.
10.1038/s42005-023-01145-9
Report
The paper gives a nice overview of the motivation and simulation method used, as well as describing the observed collisions and their aftermath. However, it is missing information on the larger implications of this work, specifically, for use in computing applications and linking with larger body of work done with skyrmions in magnetic materials. Lastly, the paper seems to ignore some relevant work done on dynamics of chiral skyrmions.
Requested changes
1. Add references to past work
2. Explain the exact choice of material parameters used
3. Address the weakness points listed above
Recommendation
Ask for major revision
Strengths
1-clearly written and structured
2-numerical discovery of new type of skyrmion scattering with associated scale change in antiferromagnetic materials
3- clear discussion of the results, with good set of references
Weaknesses
1-lack of an understanding of the scale change during the skyrmion scattering
Report
This is an interesting account of a novel phenomenon in magnetic skyrmion interactions. While this adds an interesting phenomenon to the long list of different types of skyrmion interaction behaviour, it is hardly a groundbreaking discovery. Neither does it open new synergetic links or pathways for skyrmion research. In that sense it does not meet the expectations of SciPost
Requested changes
Towards the end of the paper the authors begin a discussion of how one might understand the interaction behaviour they observe numerically. This discussion is merely a sketch at the moment: it contains unjustified assumptions (`Assuming that f_2 is larger ...'). The authors should justify this assumption and pursue the analytical study to produce an understanding of the interaction behaviour.
Recommendation
Ask for major revision