title: Edge modes in zigzag and armchair ribbons of monolayer MoS2.
abstract: We explore the electronic structure, orbital character and topological aspect of a monolayer MoS2nanoribbon using tight-binding (TB) and low-energy ([Formula: see text]) models. We obtain a mid-gap edge mode in the zigzag ribbon of monolayer MoS2, which can be traced back to the topological properties of the bulk band structure. Monolayer MoS2can be considered as a valley Hall insulator. The boundary conditions at armchair edges mix the valleys on the edges, and a gap is induced in the edge modes. The spin-orbit coupling in the valence band reduces the hybridization of the bulk states.
authors.affiliation: Istituto Italiano di Tecnologia, Graphene Labs, Via Morego 30, I-16163 Genova, Italy. School of Physics, Institute for Research in Fundamental Sciences (IPM), Tehran 19395-5531, Iran.
authors.forename: Habib
authors.initials: H
authors.lastname: Rostami
authors.forename: Reza
authors.initials: R
authors.lastname: Asgari
authors.forename: Francisco
authors.initials: F
authors.lastname: Guinea