Giant Kohn anomaly and chiral phonons in the charge density wave phase of 1H-NbSe$_2$
Fuente:
arXiv
Saved in:
| Main Authors: | , , , , , , , , |
|---|---|
| Format: | Preprint |
| Published: |
2025
|
| Subjects: | |
| Online Access: | |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866910121389457408 |
|---|---|
| author | Exists, Susy Mardanya, Sougata Markiewicz, Robert Hakioglu, Tugrul Nieminen, Jouko Härkönen, Ville J. Sanga, Cem Bansil, Arun Chowdhury, Sugata |
| author_facet | Exists, Susy Mardanya, Sougata Markiewicz, Robert Hakioglu, Tugrul Nieminen, Jouko Härkönen, Ville J. Sanga, Cem Bansil, Arun Chowdhury, Sugata |
| contents | Despite extensive investigations, many aspects of charge density waves (CDWs) remain elusive, especially the relative roles of electron-phonon coupling and Fermi surface nesting as the underlying driving mechanisms responsible for the emergence of the CDW vector $Q_{CDW}$. It is puzzling that even though electrons interact strongly with optical phonons in many correlated systems, the actual mode softening is of an acoustic mode. Here we consider monolayer 1H-NbSe$_2$ as an exemplar system, and through an accurate computation of the phonon self-energy, including its off-diagonal components, we provide compelling evidence that the relevant mode is a longitudinal optical phonon that softens by anti-crossing several intervening phonon bands, i.e. a Kohn ladder which has been only observed previously in high temperature superconductors. We also show that $Q_{CDW}$ is fixed by the convolution of the susceptibility and electron-phonon coupling, and that the softened phonons are circularly polarized. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2501_04821 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Giant Kohn anomaly and chiral phonons in the charge density wave phase of 1H-NbSe$_2$ Exists, Susy Mardanya, Sougata Markiewicz, Robert Hakioglu, Tugrul Nieminen, Jouko Härkönen, Ville J. Sanga, Cem Bansil, Arun Chowdhury, Sugata Strongly Correlated Electrons Materials Science Despite extensive investigations, many aspects of charge density waves (CDWs) remain elusive, especially the relative roles of electron-phonon coupling and Fermi surface nesting as the underlying driving mechanisms responsible for the emergence of the CDW vector $Q_{CDW}$. It is puzzling that even though electrons interact strongly with optical phonons in many correlated systems, the actual mode softening is of an acoustic mode. Here we consider monolayer 1H-NbSe$_2$ as an exemplar system, and through an accurate computation of the phonon self-energy, including its off-diagonal components, we provide compelling evidence that the relevant mode is a longitudinal optical phonon that softens by anti-crossing several intervening phonon bands, i.e. a Kohn ladder which has been only observed previously in high temperature superconductors. We also show that $Q_{CDW}$ is fixed by the convolution of the susceptibility and electron-phonon coupling, and that the softened phonons are circularly polarized. |
| title | Giant Kohn anomaly and chiral phonons in the charge density wave phase of 1H-NbSe$_2$ |
| topic | Strongly Correlated Electrons Materials Science |
| url | https://arxiv.org/abs/2501.04821 |