Surface X-ray Speckles: Coherent Surface Diffraction from Au (0 0 1)

TL;DR

This study uses coherent x-ray diffraction to analyze surface atom dynamics on Au (0 0 1), revealing temperature-dependent behaviors through speckle pattern fluctuations and auto-correlation analysis.

Contribution

It demonstrates the ability to observe and distinguish surface atomic dynamics via speckle pattern analysis in coherent x-ray diffraction.

Findings

Speckle patterns fluctuate despite static integrated intensity.

Surface dynamics vary with temperature, showing different behaviors.

Auto-correlation reveals two distinct dynamic regimes.

Abstract

We present coherent speckled x-ray diffraction patterns obtained from a monolayer of surface atoms. We measured both the specular anti-Bragg reflection and the off-specular hexagonal reconstruction peak for the Au (0 0 1) surface reconstruction. We observed fluctuations of the speckle patterns even when the integrated intensity appears static. By auto-correlating the speckle patterns, we were able to identify two qualitatively different surface dynamic behaviors of the hex reconstruction depending on the sample temperature.