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Catalogue of phonon modes in several cuprate high-temperature superconductors from density functional theory
by N. J. Jabusch, P. Dayal, A. F. Kemper
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Submission summary
| Authors (as registered SciPost users): | Noah Jabusch |
| Submission information | |
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| Preprint Link: | https://arxiv.org/abs/2010.10553v2 (pdf) |
| Code repository: | https://github.com/kemperlab/axsf-cell-conversion.git |
| Date submitted: | 2021-07-29 00:40 |
| Submitted by: | Jabusch, Noah |
| Submitted to: | SciPost Physics Core |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approaches: | Theoretical, Computational |
Abstract
Cuprates are promising candidates for study in developing higher temperature superconductors. A thorough understanding of a material's phonon modes enables further investigation of its emergent properties, however, no complete reference of the phonon modes exists. Here, using density functional theory, we evaluate the phonon frequencies and atomic displacements for $\text{La}_2\text{CuO}_4$, $\text{Bi}_2\text{Sr}_2\text{CuO}_6$, and $\text{Bi}_2\text{Sr}_2\text{CaCu}_2\text{O}_8$ in their tetragonal structures. The phonon modes for all materials agree with those expected from space group symmetry and display instabilities corresponding to known low-temperature structural phase transitions.
Current status:
Reports on this Submission
Report #1 by Anonymous (Referee 2) on 2021-12-6 (Invited Report)
- Cite as: Anonymous, Report on arXiv:2010.10553v2, delivered 2021-12-06, doi: 10.21468/SciPost.Report.4006
Strengths
1) the paper presents a catalogue of the phonon modes in three representative high-Tc cuprate superconductor based on the DFT.
2) the calculations are strightforward
3) the presentation is clear
Weaknesses
1) it is not clear how close the relaxed structure used in these calculations is to the actual experimentally measured (especially for the oxygen position). The problem is that even a few percent differences might become crucail for the phonons. Given that 214 is an antiferromagnetic insulator whereas it is a non-magnetic metal in the DFT I am a bit concerned about the accuracy of the calculations. In any case the authors should discuss this.
2) could the authors also show not only the tabular frequencies of various phonons but also the spectrum plot F(\omega) to see if the phonons are overall stable (i.e. there are no negative dispersions) and discuss this in the manuscript. I am a bit afraid that non-magnetic DFT calculations can show some negative dispersions, signalling some problems in not accounting for the effect of the magnetism in the calculations. For the reference the authors could orient themselves to the classical work
Europhys. Lett., 64 (1), pp. 104-110 (2003)
3) Overall I think the Introduction will benefit from having
a bit broader discussion on the role of phonons in the field of High-Tc and the ambiguity of the alpha^2F(omega) extracted from DFT and claimed in the recent experiments. In the context of YBaCuO superconductors some works on the phonons have been made
Report
Overall I believe the paper might be interesting provided the authors make an iteration to improve the presentation reflecting the weak points (critical remarks) outlined above. Once the authors provide a satisfactory explanation the paper can be recommended for publication