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Intertwining orbital current order and superconductivity in Kagome metal
by Hyeok-Jun Yang, Hee Seung Kim, Min Yong Jeong, Yong Baek Kim, Myung Joon Han, SungBin Lee
This Submission thread is now published as
Submission summary
| Authors (as registered SciPost users): | SungBin Lee |
| Submission information | |
|---|---|
| Preprint Link: | https://arxiv.org/abs/2203.07365v2 (pdf) |
| Date accepted: | 2022-10-06 |
| Date submitted: | 2022-09-15 03:21 |
| Submitted by: | Lee, SungBin |
| Submitted to: | SciPost Physics |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approach: | Theoretical |
Abstract
The nature of superconductivity in newly discovered Kagome materials, $\text{AV}_3\text{Sb}_5$ (A=K, Rb, Cs), has been a subject of intense debate. Recent experiments suggest the presence of orbital current order on top of the charge density wave (CDW) and superconductivity. Since the orbital current order breaks time-reversal symmetry, it may fundamentally affect possible superconducting states. In this work, we investigate the mutual influence between the orbital current order and superconductivity in Kagome metal with characteristic van Hove singularity (vHS). By explicitly deriving the Landau-Ginzburg theory, we classify possible orbital current order and superconductivity. It turns out that distinct unconventional superconductivities are expected, depending on the orbital current ordering types. Thus, this information can be used to infer the superconducting order parameter when the orbital current order is identified and vice versa. We also discuss possible experiments that may distinguish such superconducting states coexisting with the orbital current order.
Author comments upon resubmission
We are resubmitting our manuscript "Intertwining orbital current order and superconductivity in Kagome metal". Based on three referee's comments, we have completed the response letter and changed our manuscript for clarification.
List of changes
List of changes
1. Introduction
On the third paragraph, after the sentence “Considering the spin degrees of freedom, … SC order parameter.”, we add a sentence to emphasize the importance of iCDW order.
“It turns out that the orbital current order is closely related to both the non-trivial band topology and unconventional SC order parameters.”
3. iCDW patterns
We move the figs. 5 and 6 from the Appendix to Section 3 for clarity. The Appendix C Edge spectrum is erased and a sentence is added below Eq. (5).
“In Fig. 2, we exhibit the Peierls phases and the plaquette fluxes for 4 iCDW patterns.”
and at the end of Section 3, a small paragraph is added.
“Here, we exhibit the edge spectrum and ... in Fig. 3.”
4.2. Total free energy
Starting the subsection, we add a sentence to explain the ansatz considering the intra-pairing (s-, d-wave SC orders) only.
“In the perfect nesting, Eq. (2), since the particle-particle susceptibility on the same patch is predominant, we focus on the SC order parameters which pair intra-patch excitations.”
6. Discussion
On the third paragraph, after the sentence “The onset temperatures … other external perturbations.”, we add a sentence for motivate future research by tuning our simplified model. We also add another sentence to emphasize required future work for realistic applications to the Kagome metals.
“We expect that triplet superconductivity such as f-wave order might be also significant by tuning microscopic parameters on our simplified model.”
“For realistic applications to the V-based Kagome metals, the multi-orbital nature of the vHS needs to be taken into account.”
B. Microscopic Hamiltonian
At the end of Appendix B, a sentence was added.
“In the presence both iCDW and SC order parameters, the spectral functions for the Bogoliubov Hamiltonian are shown in Fig. 7.”
Published as SciPost Phys. Core 6, 008 (2023)
Reports on this Submission
Report #2 by Anonymous (Referee 5) on 2022-9-26 (Invited Report)
- Cite as: Anonymous, Report on arXiv:2203.07365v2, delivered 2022-09-26, doi: 10.21468/SciPost.Report.5772
Report
I deem the authors' response fair. However, in my opinion it also demonstrates the limited scope of this manuscript that considers the highly simplified situation of the single-band model with the purely imaginary CDW. These simplifications can not be reasonably justified in AV3Sb5 or any other kagome metal that has been studied experimentally. Even if some experimental implications are given in Section 5, they would not be relevant to any realistic situation. For example, the C3 symmetry of LDOS measured by STM is proposed as one of the fingerprints of the superconducting state (Fig. 5), but in AV3Sb5 both six-fold and three-fold symmetries are already lifted by the real part of the CDW that results in a sizable modulation of the atomic positions / charge density [arXiv:2110.11306; arXiv:2203.15057; PRB 105, 195136 (2022); arXiv:2208.01499]. Therefore, the proposed experiment will not give any information in this case.
On reading through the authors' response, I could not find any statement on how their manuscript meets the acceptance criteria of SciPost Physics. Unless I miss some important message hidden between the lines, I would have a hard time justifying why this paper should appear in the journal that seeks to "detail a groundbreaking discovery, present a breakthrough, or open a new pathway with clear potential for multipronged follow-up work". Therefore, I can recommend publication in SciPost Phys. Core only.