SKM 2023 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 40: Focus Session: Frontiers of Electronic-Structure Theory VI (joint session O/HL)

HL 40.1: Talk

Thursday, March 30, 2023, 10:30–10:45, TRE Ma

Nailing down charge-density-wave phase-transition temperatures with downfolding approaches — •Arne Schobert¹, Jan Berges², Michael Sentef³, Erik van Loon⁴, Sergey Brener¹, Mariana Rossi³, and Tim Wehling¹ — ¹University of Hamburg, Germany — ²University of Bremen, Germany — ³MPSD, Hamburg, Germany — ⁴Lund University, Sweden

The coupled dynamics of electrons and nuclei is an extremely complex problem of relevance to multiple branches of sciences. Ab initio molecular dynamics (AIMD) simulations are often challenging — especially in large systems, on long time scales, in non-equilibrium or in presence of strong correlation. We can overcome these problems by mapping the full ab initio density functional theory (DFT) Hamiltonian onto a low-energy lattice model through downfolding. Three different downfolding strategies based on constraining, unscreening and combinations thereof are compared. The best performing model, which properly accounts for anharmonicity, is combined with path integral molecular dynamics (PIMD). This allows us to nail down the transition temperatures of charge-density waves — for instance in 1H-TaS2.