Journal article

Downfolding electron-phonon Hamiltonians from ab initio calculations: Application to K3 picene

  • Giovannetti, Gianluca CNR-IOM-Democritos National Simulation Centre and International School for Advanced Studies, Trieste, Italy
  • Casula, Michele CNRS and Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Université Pierre et Marie Curie, Paris, France
  • Werner, Philipp Department of Physics, University of Fribourg, Switzerland
  • Mauri, Francesco CNR-IOM-Democritos National Simulation Centre and International School for Advanced Studies, Trieste, Italy
  • Capone, Massimo CNR-IOM-Democritos National Simulation Centre and International School for Advanced Studies, Trieste, Italy
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    29.09.2014
Published in:
  • Physical Review B. - 2014, vol. 90, no. 11, p. 115435
English We propose an electron-phonon parametrization which is constructed to reproduce target geometry and harmonic frequencies taken from first principles calculations or experiment. With respect to standard electron-phonon models, it adds a “double-counting” correction, which takes into account the lattice deformation as the system is dressed by low-energy electron-phonon processes. We show the importance of this correction by studying potassium-doped picene (K3 picene), recently claimed to be a superconductor with a Tc of up to 18 K. The Hamiltonian parameters are derived from ab initio density functional theory, and the lattice model is solved by dynamical mean-field theory. Our calculations include the effects of electron-electron interactions and local electron-phonon couplings. Even with the inclusion of a strongly coupled molecular phonon, the Hubbard repulsion prevails and the system is an insulator with a small Mott gap of ≈0.2 eV.
Faculty
Faculté des sciences et de médecine
Department
Département de Physique
Language
  • English
Classification
Physics
License
License undefined
Identifiers
Persistent URL
https://folia.unifr.ch/unifr/documents/304154
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