Berlin 2018 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 42: Charge Order
TT 42.7: Talk
Tuesday, March 13, 2018, 12:00–12:15, HFT-FT 131
Competition of strong charge and spin fluctuations in monolayer NbS2 — •Erik van Loon1, Malte Rösner2,3, Gunnar Schönhoff3, Mikhail Katsnelson1, and Tim Wehling3 — 1Radboud Universiteit, Nijmegen, Nederland — 2University of Southern California, Los Angeles, USA — 3Universität Bremen, Bremen, Deutschland
Single-layers of transition metal dichalcogenides have rich phase diagrams featuring metallic, insulating and charge/spin density wave phases. Competing interactions lie beneath these competing phases. Theoretical descriptions have so far focussed on the electron-phonon interactions in these materials, whereas the electron-electron interaction has mostly been ignored. In this talk, we show that in NbS2 the local Coulomb interaction is by itself strong enough to turn the material insulating. Screening by the electron-phonon and the non-local Coulomb interaction restores the metallic phase, leads to a broadening of the electronic spectral function and to a coexistence of strong charge and spin fluctuations. These results are obtained by combining an ab-initio determination of the band structure and Coulomb interaction with the Dual Boson approach for the extended Hubbard model.