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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 8: Crystal Structure / Real Structure / Microstructure

KFM 8.4: Talk

Wednesday, September 29, 2021, 11:30–11:45, H1

Electronically driven anharmonicity in charge-density-wave materials — •Arne Schobert¹, Jan Berges¹, Erik van Loon^1,2, Michael Sentef³, and Tim Wehling¹ — ¹Institut für Theoretische Physik, Bremen Center for Computational Materials Science, and MAPEX Center for Materials and Processes, Otto-Hahn-Allee 1, Universität Bremen, D-28359 Bremen, Germany — ²Department of Physics, Lund University, Lund, Sweden — ³Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany

Charge-density waves (CDWs) occupy an important position in the phase diagram of low- dimensional systems such as the transition metal dichalcogenide monolayers. Although a CDW can often be identified already from the undistorted structure in linear response, anharmonic effects are eventually responsible for the stabilization of the distorted phase and its precise properties. To study the mechanisms responsible for the anharmonicity, we calculate Born-Oppenheimer potential energy surfaces for lattice distortions in 1T-TaS2, 1T-VS2, and 2H-NbSe2, and we establish a connection to the electronic structure of these materials.

Financial support by the Deutsche Forschungsgemeinschaft (DFG) through GRK 2247, EXC 2077 and the Emmy Noether program (SE 2558/2), the European Graphene Flagship, and the Zentrale Forschungsförderung of the Universität Bremen is gratefully acknowledged.