Collective modes and Raman response in Ta$_2$NiSe$_5$
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arXiv
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| Autori principali: | , , |
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| Natura: | Preprint |
| Pubblicazione: |
2024
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| _version_ | 1866913994120364032 |
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| author | Chatterjee, Banhi Mravlje, Jernej Golež, Denis |
| author_facet | Chatterjee, Banhi Mravlje, Jernej Golež, Denis |
| contents | We explore the collective response in an excitonic insulator phase in Ta$_2$NiSe$_5$ using a semirealistic model including relevant lattice and electronic instabilities. We calculate order-parameter susceptibility and Raman response within a time-dependent Hartree-Fock approach. Contrary to the standard expectations, the amplitude mode frequency does not coincide with the single-particle gap but has a higher frequency. We find a phase mode that is massive because the excitonic condensation breaks a discrete symmetry only and that becomes heavier as the electron-lattice coupling is increased. These features are expected to apply to generic realistic excitonic insulators. We discuss scenarios under which the phase mode does not appear as a sharp in-gap resonance. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2403_18083 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Collective modes and Raman response in Ta$_2$NiSe$_5$ Chatterjee, Banhi Mravlje, Jernej Golež, Denis Strongly Correlated Electrons We explore the collective response in an excitonic insulator phase in Ta$_2$NiSe$_5$ using a semirealistic model including relevant lattice and electronic instabilities. We calculate order-parameter susceptibility and Raman response within a time-dependent Hartree-Fock approach. Contrary to the standard expectations, the amplitude mode frequency does not coincide with the single-particle gap but has a higher frequency. We find a phase mode that is massive because the excitonic condensation breaks a discrete symmetry only and that becomes heavier as the electron-lattice coupling is increased. These features are expected to apply to generic realistic excitonic insulators. We discuss scenarios under which the phase mode does not appear as a sharp in-gap resonance. |
| title | Collective modes and Raman response in Ta$_2$NiSe$_5$ |
| topic | Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2403.18083 |