Simon Oddsson Mariager – Niels Bohr Institute - University of Copenhagen

Simon Oddsson Mariager

Title: Structure and dynamics of crystalline

A thesis submitted in june, 2010 for the degree of Doctor of Philosophy and defended august 26, 2010.

Centre for Molecular Movies, Niels Bohr Institute, Faculty of Science, University of Copenhagen, Denmark.

Robert Feidenhans'l

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Structure and dynamics of crystalline

In this thesis we describe two types of experiments based on x-ray diffraction.

The basics of the kinematical theory of x-ray diffraction is introduced and the diffractometer calculations necessary to perform an x-ray diffraction experiment and produce reciprocal space maps are presented. These techniques are used to perform a series of measurement on the structure and growth of GaAs nanowires. The second type of diffraction experiments are time-resolved laser pump x-ray probe xperiments performed at the FEMTO beamline of SLS. The first experiment concerns the electronic deformation of metals.

We study the laser induced strain waves in a Au crystal and model the results with numerical solutions of the two temperature model and continuum equation of motion. In the second experiment we study the structural part of the anti-ferromagnetic to ferromagnetic phase transition in FeRh. Finally we couple the two parts of the thesis in a time-resolved x-ray study of laser excited acoustic oscillations in InAs nanowires.

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