Analysis of long-lived effects in high-repetition-rate stroboscopic transient X-ray absorption experiments on thin films
Abstract
Time-resolved X-ray absorption spectroscopy (tr-XAS) has been shown to be a versatile measurement technique for investigating non-equilibrium dynamics. Novel X-ray free electron laser (XFEL) facilities like the European XFEL offer increased repetition rates for stroboscopic XAS experiments through a burst operation mode, which enables measurements with up to 4.5 MHz. These higher repetition rates lead to higher data acquisition rates but can also introduce long-lived excitations that persist and thus build up during each burst. Here, we report on such long-lived effects in Ni and NiO thin film samples that were measured at the European XFEL. We disentangle the long-lived excitations from the initial pump-induced change and perform a detailed modelling-based analysis of how they modify transient X-ray spectra. As a result, we link the long-lived effects in Ni to a local temperature increase, as well as the effects in NiO to excited charge carrier trapping through polaron formation. In addition, we present possible correction methods, as well as discuss ways in which the effects of these long-lived excitations could be minimized for future time-resolved X-ray absorption spectroscopy measurements.
Cite
@article{arxiv.2412.05151,
title = {Analysis of long-lived effects in high-repetition-rate stroboscopic transient X-ray absorption experiments on thin films},
author = {Tobias Lojewski and Loïc Le Guyader and Naman Agarwal and Christine Boeglin and Robert Carley and Andrea Castoldi and Carsten Deiter and Robin Y. Engel and Florian Erdinger and Hans Fangohr and Carlo Fiorini and Natalia Gerasimova and Rafael Gort and Frank de Groot and Karsten Hansen and Steffen Hauf and David Hickin and Manuel Izquierdo and Lea Kämmerer and Benjamin E. Van Kuiken and David Lomidze and Stefano Maffessanti and Laurent Mercadier and Giuseppe Mercurio and Piter S. Miedema and Matthias Pace and Matteo Porro and Javad Rezvani and Nico Rothenbach and Benedikt Rösner and Andrey Samartsev and Justina Schlappa and Christian Stamm and Martin Teichmann and Monica Turcato and Alexander Yaroslavtsev and Florian Döring and Andreas Scherz and Christian David and Martin Beye and Uwe Bovensiepen and Heiko Wende and Andrea Eschenlohr and Katharina Ollefs},
journal= {arXiv preprint arXiv:2412.05151},
year = {2024}
}