Twins and their boundaries during homoepitaxy on Ir(111)

TL;DR

This study investigates the formation, structure, and annealing behavior of twinned homoepitaxial films on Ir(111), using advanced microscopy and diffraction techniques to understand twin boundary dynamics.

Contribution

It introduces a novel in situ X-ray diffraction method for quantifying twin fractions and models the structure of twin boundaries during annealing.

Findings

Twin boundaries reduce in length before twins disappear during annealing.

Surface X-ray diffraction effectively determines twin fractions in multilayer films.

A structural model of side twin boundaries aligns with microscopy and diffraction data.

Abstract

The growth and annealing behavior of strongly twinned homoepitaxial films on Ir(111) has been investigated by scanning tunneling microscopy, low energy electron diffraction and surface X-ray diffraction. In situ surface X-ray diffraction during and after film growth turned out to be an efficient tool for the determination of twin fractions in multilayer films and to uncover the nature of side twin boundaries. The annealing of the twin structures is shown to take place in a two step process, reducing first the length of the boundaries between differently stacked areas and only then the twins themselves. A model for the structure of the side twin boundaries is proposed which is consistent with both the scanning tunneling microscopy and surface X-ray diffraction data.