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Theoretical investigations on Kerr and Faraday rotations in topological multi-Weyl Semimetals
by Supriyo Ghosh, Ambaresh Sahoo, Snehasish Nandy
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Submission summary
| Authors (as registered SciPost users): | Snehasish Nandy |
| Submission information | |
|---|---|
| Preprint Link: | https://arxiv.org/abs/2209.11217v4 (pdf) |
| Date submitted: | 2023-02-28 18:16 |
| Submitted by: | Nandy, Snehasish |
| Submitted to: | SciPost Physics |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approach: | Theoretical |
Abstract
Motivated by the recent proposal of giant Kerr rotation in WSMs, we investigate the Kerr and Faraday rotations in time-reversal broken multi-Weyl semimetals (mWSMs) in the absence of an external magnetic field. Using the framework of Kubo response theory, we find that both the longitudinal and transverse components of the optical conductivity in mWSMs are modified by the topological charge ($n$). Engendered by the optical Hall conductivity, we show in the thin film limit that, while the giant Kerr rotation and corresponding ellipticity are independent of $n$, the Faraday rotation and its ellipticity angle scale as $n$ and $n^2$, respectively. In contrast, the polarization rotation in semi-infinite mWSMs is dominated by the axion field showing $n$ dependence. In particular, the magnitude of Kerr (Faraday) angle decreases (increases) with increasing $n$ in Faraday geometry, whereas in Voigt geometry, it depicts different $n$-dependencies in different frequency regimes. The obtained results on the behavior of polarization rotations in mWSMs could be used in experiments as a probe to distinguish single, double, and triple WSMs, as well as discriminate the surfaces of mWSMs with and without hosting Fermi arcs.
Author comments upon resubmission
List of changes
List of changes
Summary of changes in response to referee report
1) In response to referee comment 1, we have added a comment on possible candidate materials along with two new references (Refs. ~61 and 62) in the revised version of the manuscript. (First paragraph, Left column, Page 11)
2) In response to referee comment 2, we have added a comment on momentum cutoff of our low-energy model in the revised manuscript. (First Paragraph, Right Column, Page 4)
3) In response to referee comment 3, we have added clarifications on the polarization rotation of the transmitted light in both Faraday geometry and Voigt geometry. We have also discussed the experimental realization of polarization rotations using our results, and added new references (Refs.~56, 57, 59 and 60) in the revised manuscript (Second paragraph, Left column, Page 9; Third paragraph, Left column, Page 10). We have also modified the abstract and conclusions accordingly.
4) In response to referee comment 4, we have added clarifications on the role of thickness of the thin film and multiple reflection in Kerr rotation in the revised manuscript (First Paragraph, Left Column, Page 7). We have also added a comment on the range of thickness and wavelength of the incident light in the revised manuscript. (Third Paragraph, Left Column, Page 7)
5) In response to referee comment 5, we have added a comment on the tilt parameter (First paragraph, Left column, Page 4). We have also corrected the typo in the revised manuscript.
6) We have elaborated the off-diagonal conductivity part in the revised manuscript in response to referee comment 6 and added a new reference (Ref.~51). (Right Column, Page 5)
Current status:
Reports on this Submission
Report #1 by Anonymous (Referee 2) on 2023-7-14 (Contributed Report)
- Cite as: Anonymous, Report on arXiv:2209.11217v4, delivered 2023-07-14, doi: 10.21468/SciPost.Report.7502
Report
The manuscript analyzes optical properties of a magnetic multi-Weyl semimetal and identifies the signatures of the order of the Weyl node (topological charge) by studying Faraday and Kerr effects.
In the first round of review another referee identified two limitations of the manuscript: the lack of discussion of possible materials and a missing discussion of energy scales as well as raised some technical issues. I have found that the authors have appropriately addressed these issues in the resubmitted version of the manuscript and in their report to the first referee.
I agree with the recommendation of the first referee to recommend the paper to SciPost Physics. However I believe the discussion in the manuscript would be made stronger if the authors explicitly explain:
- What are the qualitative differences between $n=1$ (conventional WSM) and $n>1$ (mWSM).
- Which of the signatures would remain visible in presence of additional trivial bands present on the Fermi level.
With these extensions I am happy to recommend the manuscript to SciPost Physics.
Author: Snehasish Nandy on 2023-07-21 [id 3826]
(in reply to Report 1 on 2023-07-14)We are grateful to the Referee for his/her report and recommending our work for publication. Please find our response to the comments from the Referee in the attached file.
Attachment:
Referee_Response_1.pdf