Antichiral edge states in a modified Haldane nanoribbon

TL;DR

This paper introduces a novel topological phase featuring antichiral edge states that propagate in the same direction on both edges, with potential for robust transport even under disorder, and suggests an experimental realization in transition metal dichalcogenides.

Contribution

The authors propose a new topological phase with antichiral edge modes, differing from conventional chiral states, and demonstrate its properties through models and simulations.

Findings

Antichiral edge modes propagate in the same direction on both edges.

Backscattering is suppressed despite strong disorder.

Experimental realization is feasible in transition metal dichalcogenide monolayers.

Abstract

Topological phases of fermions in two-dimensions are often characterized by chiral edge states. By definition these propagate in the opposite directions at the two parallel edges when the sample geometry is that of a rectangular strip. We introduce here a model which exhibits what we call "antichiral" edge modes. These propagate in the same direction at both parallel edges of the strip and are compensated by counter-propagating modes that reside in the bulk. General arguments and numerical simulations show that backscattering is suppressed even when strong disorder is present in the system. We propose a feasible experimental realization of a system showing such antichiral edge modes in transition metal dichalcogenide monolayers.