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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.