Perfectly conducting channel on the dark surface of weak topological insulators

TL;DR

This paper predicts the existence of a single pair of perfectly conducting 1D channels on the dark surface of weak topological insulators, arising from atomic islands or crystal dislocations, revealing novel surface conduction phenomena.

Contribution

It introduces the concept of perfectly conducting channels on the dark surface of WTIs, a phenomenon not previously identified, linked to atomic islands and dislocations.

Findings

Single pair of 1D conducting channels predicted

Channels form from atomic islands or dislocations

Channels are perfectly conducting and isolated

Abstract

A weak topological insulator (WTI) bears, generally, an even number of Dirac cones on its surface; they are susceptible of doubling, while on the surface of a certain orientation it shows no Dirac cone. On this "dark" surface of a WTI, we predict the existence of a single pair of isolated 1D perfectly conducting channels that forms either a closed loop or a segment of a line. The former is associated typically with a single atomic-layer-thick island formed on the dark surface, while the latter is shown to be the consequence of a pair of crystal (screw) dislocations terminating on the dark surface.