We study the influence of strong spin-orbit interaction on the formation of flat bands in relaxed twisted bilayer WSe2. Flat bands, well separated in energy, emerge at the band edges for twist angles (θ) near 0∘ and 60∘. For θ near 0∘, the interlayer hybridization together with a moir\'{e} potential determines the electronic structure. The bands near the valence band edge have nontrivial topology, with Chern numbers equal to +1 or −1. We propose that the nontrivial topology of the first band can be probed experimentally for twist angles less than a critical angle of 3.5∘. For θ near 60∘, the flattening of the bands arising from the K point of the unit cell Brillouin zone is a result of atomic rearrangements in the individual layers. Our findings on the flat bands and the localization of their wavefunctions for both ranges of θ match well with recent experimental observations.
@article{arxiv.2103.07447,
title = {Moir\'{e} induced topology and flat bands in twisted bilayer WSe$_2$: A first-principles study},
author = {Sudipta Kundu and Mit H. Naik and H. R. Krishnamurthy and Manish Jain},
journal= {arXiv preprint arXiv:2103.07447},
year = {2022}
}