Interaction between electronic structure and strain in Bi nanolines on Si(001)

TL;DR

This study combines experimental STM imaging and first-principles calculations to explore how strain from Bi nanolines on Si(001) influences local atomic and electronic structures, revealing strain-mediated interactions.

Contribution

It provides new insights into the strain-induced electronic and atomic modifications in Bi nanolines on Si(001) through combined experimental and theoretical analysis.

Findings

Strain from Bi nanolines affects neighboring Si dimers' structure and electronic properties.

Identified the mechanism of strain interaction between nanolines and silicon substrate.

Compared electronic structures of nanolines with different surface passivations.

Abstract

Heteroepitaxial strain can be a controlling factor in the lateral dimensions of 1-D nanostructures. Bi nanolines on Si(001) have an atomic structure which involves a large sub-surface reconstruction, resulting in a strong elastic coupling to the surrounding silicon. We present variable-bias STM and first principles electronic structure calculations of the Bi nanolines, which investigates this interaction. We show that the strain associated with the nanolines affects the atomic and electronic structure of at least two neighbouring Si dimers, and identify the mechanism behind this. We also present partial charge densities (projected by energy) for the nanoline with clean and hydrogenated surroundings and contrast it to the clean Si(001) surface.