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arXiv · 1911.06201

Effect of lattice excitations on transient near edge X-ray absorption spectroscopy

N. Rothenbach·M. E. Gruner·K. Ollefs·C. Schmitz-Antoniak·S. Salamon·P. Zhou·R. Li·M. Mo·S. Park·X. Shen·S. Weathersby·J. Yang·X. J. Wang·O. Šipr·H. Ebert·K. Sokolowski-Tinten·R. Pentcheva·U. Bovensiepen·A. Eschenlohr·H. Wende
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Abstract

Time-dependent and constituent-specific spectral changes in soft near edge X-ray spectroscopy (XAS) of an [Fe/MgO]$_8$ metal/insulator heterostructure upon laser excitation are analyzed at the O K-edge with picosecond time resolution. The oxygen absorption edge of the insulator features a uniform intensity decrease of the fine structure at elevated phononic temperatures, which can be quantified by a simple simulation and fitting procedure presented here. Combining X-ray absorption spectroscopy with ultrafast electron diffraction measurements and ab initio calculations demonstrate that the transient intensity changes in XAS can be assigned to a transient lattice temperature. Thus, the sensitivity of transient near edge XAS to phonons is demonstrated.

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N. Rothenbach, M. E. Gruner, K. Ollefs, C. Schmitz-Antoniak, S. Salamon, P. Zhou, R. Li, M. Mo, S. Park, X. Shen, S. Weathersby, J. Yang, X. J. Wang, O. Šipr, H. Ebert, K. Sokolowski-Tinten, R. Pentcheva, U. Bovensiepen, A. Eschenlohr, H. Wende. 2019-11-14. Effect of lattice excitations on transient near edge X-ray absorption spectroscopy. https://doi.org/10.1103/physrevb.104.144302

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