Berlin 2018 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 99: 2D materials beyond graphene: TMDCs, silicene and relatives IV

O 99.8: Vortrag

Donnerstag, 15. März 2018, 17:00–17:15, MA 043

Electronic structure of single layer 1T-NbSe₂: interplay of lattice distortions, non-local exchange and Mott Hubbard correlations — •Ebad Kamil, Jan Berges, Gunnar Schönhoff, Malte Schüler, and Tim Wehling — Institut für Theoretische Physik, Universität Bremen, Bremen, Germany.

Transition metal dichalcogenides (TMDCs) often occur in two different crystal phases with octahedral (1T) and trigonal prismatic (2H) symmetry. For NbSe₂, the 2H phase has been known to be the most stable and easier to synthesize polymorph. However, recently 1T-NbSe₂ in the monolayer limit was synthesized epitaxially on a bilayer graphene and was suggested to be a Mott insulator [Yuki Nakata et al. NPG Asia Materials (2016) 8, e321] with √13×√13 periodic density modulation. We perform ab-initio calculations to understand the emergence of an insulating behavior and charge density wave (CDW) in the monolayer 1T-NbSe₂, which otherwise is predicted to be a metal in DFT and GW calculations. We provide an estimate for the local and non-local screened Coulomb interaction within the ab-initio formalism and present the findings of LDA+DMFT simulations that suggest the possibility of opening of a Mott insulating gap in the CDW phase.