Role of the spin-orbit splitting and the dynamical fluctuations in the Si(557)-Au surface

TL;DR

This study uses ab initio calculations to show that spin-orbit coupling explains the electronic structure of Si(557)-Au, and reveals that temperature-dependent fluctuations cause a Peierls-like transition, impacting potential device applications.

Contribution

It demonstrates the importance of spin-orbit coupling in understanding Si(557)-Au's electronic structure and clarifies the origin of the observed transition as due to dynamical fluctuations.

Findings

Spin-orbit splitting explains the two 1D bands in photoemission.

Dynamical fluctuations cause the Peierls-like transition.

Fluctuations are quenched at lower temperatures.

Abstract

Our it ab initio calculations show that spin-orbit coupling is crucial to understand the electronic structure of the Si(557)-Au surface. The spin-orbit splitting produces the two one-dimensional bands observed in photoemission, which were previously attributed to spin-charge separation in a Luttinger liquid. This spin splitting might have relevance for future device applications. We also show that the apparent Peierls-like transition observed in this surface by scanning tunneling microscopy is a result of the dynamical fluctuations of the step-edge structure, which are quenched as the temperature is decreased.