Lattice reconstruction in twisted transition-metal dichalcogenide (TMD) bilayers gives rise to piezo- and ferroelectric moir\'e potentials for electrons and holes, as well as a modulation of the hybridisation across the bilayer. Here, we develop hybrid k⋅p tight-binding models to describe electrons and holes in the relevant valleys of twisted TMD homobilayers with parallel (P) and anti-parallel (AP) orientations of the monolayer unit cells. We apply these models to describe moir\'e superlattice effects in twisted WSe2 bilayers, in conjunction with microscopic \emph{ab initio} calculations, and considering the influence of encapsulation, pressure and an electric displacement field. Our analysis takes into account mesoscale lattice relaxation, interlayer hybridisation, piezopotentials, and a weak ferroelectric charge transfer between the layers, and describes a multitude of possibilities offered by this system, depending on the choices of P or AP orientation, twist angle magnitude, and electron/hole valley.
@article{arxiv.2106.06058,
title = {Multifaceted moir\'e superlattice physics in twisted WSe$_2$ bilayers},
author = {S. J. Magorrian and V. V. Enaldiev and V. Zólyomi and Fábio Ferreira and Vladimir I. Fal'ko and David A. Ruiz-Tijerina},
journal= {arXiv preprint arXiv:2106.06058},
year = {2021}
}
Comments
44 pages, 27 figures, 6 appendices. For v2: Modelling and analysis for Q-point bands and minibands added