Phonon self-energy corrections: To screen, or not to screen

Berges, Jan; Girotto, Nina; Wehling, T. O.; Marzari, Nicola; Poncé, Samuel

doi:10.48550/arxiv.2212.11806

Cited by 2 publications

(2 citation statements)

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“…Our results are in a good agreement with refs , , and and especially with ref , where the attosecond core-level spectroscopy demonstrated that the Raman-inactive A 1 ′ mode is the dominating channel for dissipation of electronic coherence due to stronger coupling to electrons . Note also that in our calculations the acoustic sum rule is not fully fulfilled because we inhibit the long-wavelength dipole-allowed transitions , by filling the states above the Fermi energy.…”

supporting

confidence: 91%

Dynamical Phonons Following Electron Relaxation Stages in Photoexcited Graphene

Girotto,

Novko

2023

J. Phys. Chem. Lett.

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Ultrafast electron−phonon relaxation dynamics in graphene hides many distinct phenomena, such as hot phonon generation, dynamical Kohn anomalies, and phonon decoupling, yet it still remains largely unexplored. Here, we unravel intricate mechanisms governing the vibrational relaxation and phonon dressing in graphene at a highly nonequilibrium state by means of first-principles techniques. We calculate dynamical phonon spectral functions and momentum-resolved line widths for various stages of electron relaxation and find photoinduced phonon hardening, overall increase of relaxation rate and nonadiabaticity, as well as phonon gain. Namely, the initial stage of photoexcitation is found to be governed by strong phonon anomalies of finite-momentum optical modes along with incoherent phonon production. The population inversion state, on the other hand, allows the production of coherent and strongly coupled phonon modes. Our research provides vital insights into the electron−phonon coupling phenomena in graphene and serves as a foundation for exploring nonequilibrium phonon dressing in materials where ordered states and phase transitions can be induced by photoexcitation.

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confidence: 91%

Dynamical Phonons Following Electron Relaxation Stages in Photoexcited Graphene

Girotto,

Novko

2023

J. Phys. Chem. Lett.

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“…with Π 0 (q, iν n ) the RPA polarization. The full interaction is given by I 0 (q, iν n ) = I L (q, iν n ) + v TO ph (iν n ) and hosts frequency and momentum dependent screened electron-phonon [68][69][70] and electronelectron interactions including their hybridization. We evaluate the electron dispersion within a nearestneighbor square-lattice tight binding model with a hopping of t = 1.5 eV (m * ≈ 0.1 m e ) and a chemical potential yielding approximately quarter filling.…”

Section: Formalismmentioning

confidence: 99%

Screening induced crossover between phonon- and plasmon-mediated pairing in layered superconductors

in’t Veld,

Katsnelson,

Millis

et al. 2023

2D Mater.

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Two-dimensional (2D) metals can host gapless plasmonic excitations that strongly couple to electrons and thus may significantly affect superconductivity. To investigate the dynamical interplay of the electron–electron and electron–phonon interactions in the theory of 2D superconductivity, we apply a full momentum- and frequency-dependent one-loop theory treating electron–phonon, electron–plasmon, and phonon–plasmon coupling with the same accuracy. We tune the strength of the Coulomb interaction by varying the external screening ε e x t to the layered superconductor and find three distinct regions. At weak screening, superconductivity is mediated by plasmons. In the opposite limit conventional electron–phonon interactions dominate. In between, we find a suppressed superconducting state. Our results show that even in conventional electron–phonon coupled layered materials, superconductivity can be significantly enhanced by the electron–plasmon coupling in a manner that can be controlled by the external screening.

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Phonon self-energy corrections: To screen, or not to screen

Cited by 2 publications

References 0 publications

Dynamical Phonons Following Electron Relaxation Stages in Photoexcited Graphene

Dynamical Phonons Following Electron Relaxation Stages in Photoexcited Graphene

Screening induced crossover between phonon- and plasmon-mediated pairing in layered superconductors

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