2026-06-03T05:47:36Z https://archive.materialscloud.org/oai2d

oai:materialscloud.org:1909 2023-09-21T17:36:01Z openaire_data community-mcarchive

Berges, Jan Berges, Jan Girotto, Nina Wehling, Tim Marzari, Nicola Poncé, Samuel 2023-09-21 First-principles calculations of phonons are often based on the adiabatic approximation and on Brillouin-zone samplings that might not always be sufficient to capture the subtleties of Kohn anomalies. These shortcomings can be addressed through corrections to the phonon self-energy arising from the low-energy electrons. The exact self-energy involves a product of a bare and a screened electron-phonon vertex [Rev. Mod. Phys. 89, 015003 (2017)]; still, calculations often employ two adiabatically screened vertices, which have been proposed as a reliable approximation for self-energy differences [Phys. Rev. B 82, 165111 (2010)]. We assess the accuracy of both approaches in estimating the phonon spectral functions of model Hamiltonians and the adiabatic low-temperature phonon dispersions of monolayer TaS₂ and doped MoS₂. We find that the approximate method yields excellent corrections at low computational cost, due to its designed error cancellation to first order, while using a bare vertex could in principle improve these results but is challenging in practice. We offer an alternative strategy based on downfolding to partially screened phonons and interactions [Phys. Rev. B 92, 245108 (2015)]. This is a natural scheme to include electron-electron interactions and tackle phonons in strongly correlated materials and the frequency dependence of the electron-phonon vertex. This record contains (i) a patch for the PHonon and EPW codes of Quantum ESPRESSO, (ii) the Python scripts and data necessary to create all figures shown in our paper, (iii) a minimal working example of the optimization of quadrupole tensors, and (iv) the Quantum ESPRESSO input files we have used. text/markdown text/x-diff text/plain application/gzip application/gzip application/gzip application/gzip application/gzip application/gzip application/gzip application/gzip application/gzip application/gzip application/gzip application/gzip application/gzip application/gzip text/markdown https://doi.org/10.24435/materialscloud:he-pv oai:materialscloud.org:1909 mcid:2023.146 eng Materials Cloud https://doi.org/10.48550/arXiv.2212.11806 https://archive.materialscloud.org/communities/mcarchive https://doi.org/10.24435/materialscloud:by-3p info:eu-repo/semantics/openAccess GNU General Public License v2.0 or later https://www.gnu.org/licenses/old-licenses/gpl-2.0-standalone.html MARVEL/DD3 SNSF H2020 PRACE electron-phonon coupling first principles phonons 2D materials Phonon self-energy corrections: To screen, or not to screen info:eu-repo/semantics/other