Hosted by: Deyu Lu

Twisting van der Waals heterostructures to induce correlated many body states provides a novel tuning mechanism in solid state physics. In this work, we theoretically investigate the fate of the surface Dirac cone of a three-dimensional topological insulator subject to a superlattice potential. Using a combination of diagrammatic perturbation theory, lattice model simulations, and ab initio calculations we elucidate the unique aspects of twisting a single Dirac cone with an induced moire potential and the role of the bulk topology on the reconstructed surface band structure. We report a dramatic renormalization of the surface Dirac cone velocity as well as demonstrate a topological obstruction to the formation of isolated minibands. Due to the topological nature of the bulk, surface band gaps cannot open; instead additional satellite Dirac cones emerge, which can be highly anisotropic. We discuss the implications of our findings for future experiments. Ref: https://arxiv.org/abs/2010.09726 Host: Deyu Lu Webinar https://bnl.zoomgov.com/j/1617324438?pwd=aEtGa0hGK1dvSGJrNkRrZlhoZ3BIUT09 Meeting ID: 161 732 4438 Passcode: 241672