Step Patterns on Vicinal Reconstructed Surfaces

TL;DR

This paper investigates the formation of crossing step networks on vicinal Au(110) and Pt(110) reconstructed surfaces, explaining their equilibrium patterns through energy-entropy competition and confirming observations via microscopy.

Contribution

It provides a theoretical explanation for the step network patterns on reconstructed noble metal surfaces, highlighting the role of elastic energy and entropy in their formation.

Findings

Step networks form due to energy-entropy competition.

Steps are not perpendicular but form crossing networks.

Results agree with recent STM observations.

Abstract

Step patterns on vicinal $(2\times1)$ reconstructed surfaces of noble metals Au(110) and Pt(110), miscut towards the (100) orientation, are investigated. The free energy of the reconstructed surface with a network of crossing opposite steps is calculated in the strong chirality regime when the steps cannot make overhangs. It is explained why the steps are not perpendicular to the direction of the miscut but form in equilibrium a network of crossing steps which make the surface to look like a fish skin. The network formation is the consequence of competition between the -- predominantly elastic -- energy loss and entropy gain. It is in agreement with recent scanning-tunnelling-microscopy observations on vicinal Au(110) and Pt(110) surfaces.