Electronic properties of the steps in bilayer Td-WTe2

TL;DR

This study uses density functional theory to explore how atomic steps in bilayer Td-WTe2 influence the preservation or suppression of quantum spin Hall states, revealing conditions that recover these topological properties.

Contribution

It demonstrates that atomic steps can restore QSH states in bilayer WTe2, depending on their atomic structure and orientation, expanding potential applications.

Findings

QSH states are suppressed in certain stripe orientations due to layer hybridization.

Atomic steps can recover QSH states depending on their atomic structure.

Stripe orientation along y direction maintains QSH states.

Abstract

Monolayer WTe2 stripes are quantum spin Hall (QSH) insulators. Density functional theory was used for investigating the electronic properties of the stripes and steps in bilayer Td-WTe2. For the stripes oriented along the dimer chains of W atoms (x direction), the hybridization between the two layers suppresses the QSH states. However, the QSH nature can be recovered by forming a step, depending on the atomic structure of the step. Conversely, the stripes and steps along the y direction maintain the QSH states. These findings can expand the application range of the QSH states in WTe2.