Double non-equivalent chain structure on vicinal Si(557)-Au surface

TL;DR

This study investigates the electronic and topographic properties of the vicinal Si(557)-Au surface, revealing distinct metallic and semiconducting wire structures through STM and diffraction techniques, supported by theoretical modeling.

Contribution

It provides new insights into the dual wire structures on Si(557)-Au surface, identifying their material composition and electronic behavior using combined experimental and theoretical methods.

Findings

One wire exhibits metallic behavior, the other semiconducting.

STM voltage-dependent oscillations differ between the two chains.

Theoretical models suggest different material compositions for the chains.

Abstract

We study electronic and topographic properties of the vicinal Si(557)-Au surface using scanning tunneling microscopy and reflection of high energy electron diffraction technique. STM data reveal double wire structures along terraces. Moreover behavior of the voltage dependent STM tip - surface distance is different in different chains. While the one chain shows oscillations of the distance which are sensitive to the sign of the voltage bias, the oscillations in the other chain remain unchanged with respect to the positive/negative biases. This suggests that one wire has metallic character while the other one - semiconducting. The experimental results are supplemented by theoretical calculations within tight binding model suggesting that the observed chains are made of different materials, one is gold and the other one is silicon chain.