Katayun Barmak

Abstract Recent observations of superconductivity in twisted bilayer WSe2 (refs. 1,2) have extended the family of moiré superconductors beyond twisted graphene3,4,5,6,7,8,9,10,11,12,13,14,15. In WSe2, two different twist angles were studied, 3.65° (ref. 1) and 5.0° (ref. 2), and two seemingly distinct superconducting phase diagrams were reported, raising the question of whether the superconducting phases in the two devices share a similar origin.

Abstract The topological properties of Bloch bands are tied to the structure of their electronic wavefunctions within the unit cell of a crystal. Here we show that scanning tunnelling microscopy and spectroscopy measurements on the prototypical transition metal dichalcogenide semiconductor WSe2 can be used to determine the location of the Wannier centre of the valence band.

Abstract Forming long-wavelength moiré superlattices in van der Waals bilayers that have a small-angle twist between the two layers has been a key approach for creating moiré flat bands. However, for small twist angles, strong lattice reconstruction creates domain walls and other forms of disorder in the moiré pattern, posing considerable challenges for engineering such platforms.