Transmission of topological surface states through surface barriers

TL;DR

This study demonstrates that topological surface states in antimony can transmit through atomic-scale surface barriers with high probability, unlike conventional states, highlighting their potential for robust nanoscale electronic interconnects.

Contribution

It provides direct experimental evidence that topological surface states can pass through natural surface defects, unlike non-topological states, indicating their robustness for electronic applications.

Findings

Topological surface states transmit through atomic steps with high probability.

Non-topological states are reflected or absorbed by surface barriers.

Antimony's topological states are extended and resilient to surface irregularities.

Abstract

Topological surface states are a class of novel electronic states that are of potential interest in quantum computing or spintronic applications. Unlike conventional two-dimensional electron states, these surface states are expected to be immune to localization and to overcome barriers caused by material imperfection. Previous experiments have demonstrated that topological surface states do not backscatter between equal and opposite momentum states, owing to their chiral spin texture. However, so far there is no evidence that these states in fact transmit through naturally occurring surface defects. Here we use a scanning tunnelling microscope to measure the transmission and reflection probabilities of topological surface states of antimony through naturally occurring crystalline steps separating atomic terraces. In contrast to nontopological surface states of common metals (copper, silver and gold), which are either reflected or absorbed by atomic steps, we show that topological surface states of antimony penetrate such barriers with high probability. This demonstration of the extended nature of antimony's topological surface states suggests that such states may be useful for high current transmission even in the presence of atomic scale irregularities-an electronic feature sought to efficiently interconnect nanoscale devices.