Surface-dominated Conductivity of Few-layered Antimonene

TL;DR

This study theoretically demonstrates that in few-layered antimonene, surface states dominate electrical conductivity and remain metallic despite surface disorder, highlighting potential topological insulator properties.

Contribution

It reveals that surface states in few-layered antimonene dominate conductivity and are robust against surface disorder, suggesting topological insulator-like behavior without bulk insulating properties.

Findings

Surface states dominate conductivity in few-layered antimonene.

Surface states remain metallic despite surface disorder.

Bulk can become insulating while surface remains conductive.

Abstract

We present a theoretical study of the phase-coherent DC conductivity of few-layered antimonene in the presence of surface disorder. It is well known that while a single layer is a trivial semiconductor, multiple layers (typically a minimum of $\approx$ 7) turn into a semi-metal with a nontrivial topological invariant featuring protected and decoupled surface states. We employ the finite-size Kubo formalism based on density functional theory calculations to show that the conductivity is amply dominated by the topological surface states even without bulk disorder. More importantly, the conductivity of the surface states does not show traces of a metal-insulator transition while the bulk ones can be driven towards an insulating phase in presence of only surface disorder. These results suggest that few-layered antimonene, despite not being insulating in the bulk, can present many of the advantages attributed to topological insulators under very general experimental conditions.