In semiconducting transition metal dichalcogenides monolayers, the band edge carriers are described by massive Dirac cones, located at K and -K corners (valleys) of the Brillouin zone. The valley dependent properties of these massive Dirac fermions have enabled versatile control of the valley pseudospin in monolayers. Van der Waals stacking of the 2D semiconductors into vertical layered structures is a powerful approach towards designer quantum materials that can combine and extend the exotic properties of the building blocks. Ubiquitous to these vdW heterostructures is the formation of moiré́ pattern due to the inevitable lattice mismatch and twisting between the layers. We show that, uniquely for the valley massive Dirac fermions, the moiré offers unprecedented opportunities for nanoscale patterning of electronic, optical, magnetic, and topological properties. We give examples including: (i) electrically switchable lateral superstructures of topological insulators; (ii) moiré excitons for programmable arrays of quantum emitters; (iii) flux superlattice in twisted homobilayer.
Kollektorn, lecture room, Kemivägen 9, MC2-huset
27 May, 2019, 13:00
27 May, 2019, 14:00