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arXiv · 1103.0263

Persistent Oscillations of X-ray Speckles: Pt (001) Step Flow

M. S. Pierce·D. Hennessy·K. C. Chang·V. Komanicky·J. Strzalka·A. Sandy·A. Barbour·H. You
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Abstract

We have performed coherent x-ray scattering experiments on the hexagonally reconstructed Pt (001) surface to study the temperature-dependent surface dynamics. By correlating speckle patterns collected at the (001) anti-Bragg position we are able to measure surface dynamics when the averaged incoherent x-ray scattering appears static. In the temperature range above the rotational epitaxy transition and below the roughening transition (1750 K - 1830 K), we have observed well-defined oscillatory autocorrelations of speckles that persist for tens of minutes, in addition to the expected thermal decorrelation. The observed oscillations indicate surface dynamics due to "step-flow" motion. This is shown with a simple model in which the phase of the scattered x-rays from the steps within the illumination area is retained in the coherent x-ray scattering. This demonstrates a possibility that x-ray speckles can be used to monitor the real-space real-time evolution of surfaces in addition to the traditional decorrelation measurements.

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M. S. Pierce, D. Hennessy, K. C. Chang, V. Komanicky, J. Strzalka, A. Sandy, A. Barbour, H. You. 2011-09-23. Persistent Oscillations of X-ray Speckles: Pt (001) Step Flow. https://doi.org/10.1063/1.3640227

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