Publications (20)
Screening in YBCO at large wave vectors
Simo Huotari, J. Aleksi Soininen, György Vankó +2
We present experimental inelastic x-ray scattering (IXS) and ab initio time-dependent density-functional-theory (TDDFT) studies of YBa2Cu3O7-δ. The response of the low-lying Ba 5p…
Redox oscillations in 18650-type lithium-ion cell revealed by in operando Compton scattering imaging
Kosuke Suzuki, Shunta Suzuki, Yuji Otsuka +12
Compton scattering imaging using high-energy synchrotron x-rays allows the visualization of the spatio-temporal lithiation state in lithium-ion batteries probed in-operando. Here,…
Temperature dependence of crystal field excitations in CuO
Simo Huotari, Laura Simonelli, Christoph J. Sahle +3
We report a study on the temperature dependence of the charge-neutral crystal field (dd) excitations in cupric oxide, using nonresonant inelastic x-ray scattering (IXS) spectroscop…
Paramagnon dispersion and damping in doped NaCaCuOCl
Blair W. Lebert, Benjamin Bacq-Labreuil, Mark P. M. Dean +13
Using Resonant Inelastic X-ray Scattering, we measure the paramagnon dispersion and damping of undoped, antiferromagnetic CaCuOCl as well as doped, superconducting Na$_…
Towards novel probes for valence charges via X-ray optical wave mixing
Christina Boemer, Dietrich Krebs, Andrei Benediktovitch +3
We present a combined theoretical and experimental study of X-ray optical wave mixing. This class of nonlinear phenomena combines the strengths of spectroscopic techniques from the…
Exciton energy-momentum map of hexagonal boron nitride
Giorgia Fugallo, Matteo Aramini, Jaakko Koskelo +6
Understanding and controlling the way excitons propagate in solids is a key for tailoring materials with improved optoelectronic properties. A fundamental step in this direction is…
Momentum distribution and Compton profile by the ab initio GW approximation
Valerio Olevano, Andrey Titov, Massimo Ladisa +3
We present two possible approaches to calculate the momentum distribution n(p) and the Compton profile within the framework of the ab initio GW approximation on the self-energy. Th…
Monochromatic computed tomography using laboratory-scale setup: proof-of-concept
Ari-Pekka Honkanen, Simo Huotari
In this article, we demonstrate the viability of highly monochromatic full-field X-ray absorption near edge structure based tomography using a laboratory-scale Johann-type X-ray ab…
General method to calculate the elastic deformation and X-ray diffraction properties of bent crystal wafers
Ari-Pekka Honkanen, Simo Huotari
Curved single crystals are widely employed in spectrometer designs in the hard X-ray regime. Due to their large solid angle coverage and focusing properties, toroidally bent crysta…
Johann-type laboratory-scale X-ray absorption spectrometer with versatile detection modes
Ari-Pekka Honkanen, Sami Ollikkala, Taru Ahopelto +3
We present a low-cost laboratory X-ray absorption spectrometer that uses a conventional X-ray tube source and bent Johann-type crystal monochromators. The instrument is designed fo…
Tomographic X-ray data of a lotus root filled with attenuating objects
Tatiana A. Bubba, Andreas Hauptmann, Simo Huotari +2
This is the documentation of the tomographic X-ray data of a lotus root, filled with four different attenuating objects, of different sizes. Data are available at www.fips.fi/datas…
Intersite 4p-3d hybridization in cobalt oxides: a resonant x-ray emission spectroscopy study
György Vankó, Frank M. F. de Groot, Simo Huotari +3
We report on strong dipole transitions to 3d orbitals of neighboring Co atoms in the Co 1s x-ray absorption pre-edge. They are revealed by applying high-resolution resonant x-ray e…
Inner product regularized multi-energy X-ray tomography for material decomposition
Salla-Maaria Latva-Ãijö, Filippo Zanetti, Ari-Pekka Honkanen +4
Multi-energy X-ray tomography is studied for decomposing three materials using three X-ray energies and a classical energy-integrating detector. A novel regularization term compris…
Resonant X-ray Emission Spectroscopy With a Standing Wave Excitation
Kari O. Ruotsalainen, Ari-Pekka Honkanen, Stephen P. Collins +6
The Borrmann effect is the anomalous transmission of x rays in perfect crystals under diffraction conditions. It arises from the interference of the incident and diffracted waves,…
Electron-energy-loss and time-dependent density functional theory study on the plasmon dispersion in 2H-NbS2
Pierluigi Cudazzo, Eric Müller, Carsten Habenicht +5
We examine the experimental and theoretical electron-energy loss spectra in 2-CuNbS and find that the 1 eV plasmon in this material does not exhibit the regular posi…
The isotropic Compton profile difference across the phase transition of VO
Kari O. Ruotsalainen, Juho Inkinen, Tuomas Pylkkänen +4
We studied the isotropic Compton profile of the prototypical oxide VO across the temperature induced electronic and structural phase transition at T 340 K. We sho…
The Heisenberg-RIXS instrument at the European XFEL
Justine Schlappa, Giacomo Ghiringhelli, Benjamin E. Van Kuiken +44
Resonant Inelastic X-ray Scattering (RIXS) is an ideal X-ray spectroscopy method to push the combination of energy and time resolutions to the Fourier transform ultimate limit, bec…
Momentum Distribution and Renormalization Factor in Sodium and the Electron Gas
Simo Huotari, J. Aleksi Soininen, Tuomas Pylkkänen +9
We present experimental and theoretical results on the momentum distribution and the quasiparticle renormalization factor in sodium. From an x-ray Compton-profile measurement of th…
A computationally efficient method to solve the Takagi-Taupin equations for a large deformed crystal
Ari-Pekka Honkanen, Giulio Monaco, Simo Huotari
We present a treatise on solving the Takagi-Taupin equations in the case of a strain field with an additional, spatially slowly varying component (owing to \emph{e.g.}~heat expansi…
Sparse dynamic tomography. A shearlet-based approach for iodine perfusion in plant stems
Tatiana A. Bubba, Tommi Heikkilä, Hanna Help +3
In this paper we propose a motion-aware variational approach to reconstruct moving objects from sparse dynamic data. The motivation of this work stems from X-ray imaging of plants…