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O: Fachverband Oberflächenphysik
O 39: 2D Materials III: Growth and Heterostructures (joint session O/HL)
O 39.7: Vortrag
Dienstag, 17. März 2020, 12:00–12:15, GER 38
Deconfinement in van der Waals Stacks: Turning Mott Localized Electrons into Dirac Fermions — •Jose Pizarro1,2, Severino Adler3, Karim Zantout4, Thomas Mertz4, Paolo Barone5, Roser Valentí4, Giorgio Sangiovanni3, and Tim Wehling1,2 — 1University of Bremen — 2Bremen Center for Computational Material Sciences — 3University of Würzburg — 4Goethe University Frankfurt am Main — 5CNR-SPIN, Italy
The interplay of topology and electronic correlations forms a rich ground for the realization of exotic states of quantum matter, with an increased importance in emergent flat bands systems in superlattices. Here, we show how strongly correlated spin-orbit coupled Dirac fermions emerge in bilayers of 1T-TaSe2 and related group V transition metal dichalcogenides. These materials realize the so-called Star-of-David (SoD) charge density wave (CDW) patterns in each layer, where the stacking of the CDW centers defines the symmetry of the resulting superlattice. When the CDW centers are arranged in a honeycomb pattern, the system realizes a generalized Kane-Mele model with a sizable on-site Hubbard interaction U. The isoelectronic series of 1T-TaSe2, TaS2, and NbSe2 traverses a region of the electronic phase diagram where weakly-to-strongly correlated Dirac semimetallic, Mott antiferromagnetic insulating and quantum spin Hall states compete. We show that stacking and relative rotations between the layers as well as perpendicular electric fields affect the emergent correlated Dirac fermions as effective gauge and mass fields, and control their creation, annihiliation and topology.