# Sub-atomic electronic feature from dynamic motion of Si dimer defects in bismuth nanolines on Si(001)

## TL;DR

This study combines STM experiments and DFT simulations to reveal that sharp subatomic features in bismuth nanolines on Si(001) are caused by buckled Si dimers flipping during scanning, providing detailed insight into the Bi-Si(001) system.

## Contribution

It demonstrates the atomic-scale origin of unusual STM features in bismuth nanolines through combined experimental and theoretical analysis.

## Key findings

- Sharp features are due to buckled Si dimers flipping.
- DFT simulations match STM data precisely.
- Provides detailed understanding of the Bi-Si(001) Haiku system.

## Abstract

Scanning tunneling microscopy (STM) reveals unusual sharp features in otherwise defect free bismuth nanolines self-assembled on Si(001). They appear as subatomic thin lines perpendicular to the bismuth nanoline at positive biases and as atomic size beads at negative biases. Density functional theory (DFT) simulations show that these features can be attributed to buckled Si dimers substituting for Bi dimers in the nanoline, where the sharp feature is the counterintuitive signature of these dimers flipping during scanning. The perfect correspondence between the STM data and the DFT simulation demonstrated in this study highlights the detailed understanding we have of the complex Bi-Si(001) Haiku system.