Regensburg 2019 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 58: Focus Session: Electron-Phonon Interactions II
O 58.7: Vortrag
Mittwoch, 3. April 2019, 16:45–17:00, H15
Phonon renormalization in ab-initio-based lattice models — •Jan Berges1, Malte Roesner2,3, Erik van Loon1, and Tim Wehling1 — 1Institute for Theoretical Physics and Bremen Center for Computational Materials Science, University of Bremen, Germany — 2Department of Physics and Astronomy, University of Southern California, Los Angeles, USA — 3Center for Computational Quantum Physics, Flatiron Institute, New York, USA
Phonons play a major role in the understanding of phenomena such as superconductivity, periodic lattice distortions, magnetostriction, thermo- and piezoelectrics. Yet, despite the success of density-functional perturbation theory (DFPT), their ab-initio calculation remains challenging for structurally complex and strongly interacting systems. To address these problems, we introduce a computational scheme based on material-realistic quantum lattice models, that combine the efficiency of a lattice model with an ab-initio input and the freedom to choose different levels of approximation to treat electron-electron interactions. In our scheme, all parameters are derived ab initio, using the constrained methods cRPA and cDFPT [Nomura, Arita: Phys. Rev. B 92, 245108 (2015)]. In the presented work, we apply our scheme to the metallic transition-metal dichalcogenides (TMDCs), prominent showplace for coexisting many-body instabilities. First, we demonstrate that the fully renormalized ab-initio results are exactly reproduced by our model if we solve it at the level of the random-phase approximation (RPA). Then we study the influence of charge doping and hybridization with substrates.