Optical absorption and photoluminescence of single layer boron nitride from a first principles cumulant approach
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arXiv
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| Format: | Preprint |
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2024
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| _version_ | 1866913371619590144 |
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| author | Marini, Giovanni Calandra, Matteo Cudazzo, Pierluigi |
| author_facet | Marini, Giovanni Calandra, Matteo Cudazzo, Pierluigi |
| contents | The photoluminescence spectrum of a single-layer boron nitride remains elusive, marked by enigmatic satellites that hint at a significant but unidentified exciton-phonon coupling.Here, by employing a first principles approach based on the many-body cumulant expansion of the charge response, we calculate the optical absorption and photoluminescence of a single layer boron nitride. We identify the specific exciton-phonon scattering channels and unravel their impact on the optical absorption and photoluminescence spectra thereby providing an interpretation of the experimental features. Finally, we show that, even in a strongly polar material such as h-BN monolayer, the electron-hole interaction responsible for the excitonic effect results in the cancellation of the Frölich interaction at small phonon momenta. This effect is captured only if the invariance of the exciton-phonon matrix elements under unitary transformations in the Bloch functions manifold is preserved in the calculation. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2402_03826 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Optical absorption and photoluminescence of single layer boron nitride from a first principles cumulant approach Marini, Giovanni Calandra, Matteo Cudazzo, Pierluigi Materials Science The photoluminescence spectrum of a single-layer boron nitride remains elusive, marked by enigmatic satellites that hint at a significant but unidentified exciton-phonon coupling.Here, by employing a first principles approach based on the many-body cumulant expansion of the charge response, we calculate the optical absorption and photoluminescence of a single layer boron nitride. We identify the specific exciton-phonon scattering channels and unravel their impact on the optical absorption and photoluminescence spectra thereby providing an interpretation of the experimental features. Finally, we show that, even in a strongly polar material such as h-BN monolayer, the electron-hole interaction responsible for the excitonic effect results in the cancellation of the Frölich interaction at small phonon momenta. This effect is captured only if the invariance of the exciton-phonon matrix elements under unitary transformations in the Bloch functions manifold is preserved in the calculation. |
| title | Optical absorption and photoluminescence of single layer boron nitride from a first principles cumulant approach |
| topic | Materials Science |
| url | https://arxiv.org/abs/2402.03826 |