Affiner les résultats

Probing the interplay between lattice dynamics and short-range magnetic correlations in CuGeO3 with femtosecond RIXS

Paris, E. ; Nicholson, Christopher W. ; Johnston, S. ; Tseng, Y. ; Rumo, Maxime ; Coslovich, G. ; Zohar, S. ; Lin, M. F. ; Strocov, V. N. ; Saint-Martin, R. ; Revcolevschi, A. ; Kemper, A. ; Schlotter, W. ; Dakovski, G. L. ; Monney, Claude ; Schmitt, T.

In: npj Quantum Materials, 2021, vol. 6, no. 1, p. 51

Investigations of magnetically ordered phases on the femtosecond timescale have provided significant insights into the influence of charge and lattice degrees of freedom on the magnetic sub-system. However, short-range magnetic correlations occurring in the absence of long-range order, for example in spin-frustrated systems, are inaccessible to many ultrafast techniques. Here, we show how...

Mapping the unoccupied state dispersions in ${\mathrm{Ta}}_{2}{\mathrm{NiSe}}_{5}$ with resonant inelastic x-ray scattering

Monney, Claude ; Herzog, Marc ; Pulkkinen, Aki ; Huang, Y. ; Pelliciari, Jonathan ; Olalde-Velasco, P. ; Katayama, Naoyuk ; Nohara, Minoru ; Takagi, Hide ; Schmitt, Thorsten ; Mizokawa, Takashi

In: Physical Review B, 2020, vol. 102, no. 8, p. 085148

The transition metal chalcogenide Ta2NiSe5 undergoes a second-order phase transition at Tc=328K involving a small lattice distortion. Below Tc, a band gap at the center of its Brillouin zone increases up to about 0.35 eV. In this work, we study the electronic structure of Ta2NiSe5 in its low-temperature semiconducting phase, using resonant inelastic x-ray scattering (RIXS) at the Ni L3 edge....

Evaluation of resazurin-based rapid test to detect colistin resistance in Acinetobacter baumannii isolates

Germ, Julija ; Poirel, Laurent ; Cerar Kisek, Tjasa ; Cvitkovic Spik, Vesna ; Katja Seme ; Mueller Premru, Manica ; Lejko Zupanc, Tatjana ; Nordmann, Patrice ; Pirs, Mateja

In: European Journal of Clinical Microbiology & Infectious Diseases, 2019, vol. 38, no. 11, p. 2159–2162

Acinetobacter baumannii primarily causes colonization, yet it can be an opportunistic pathogen associated with hospital-acquired infections. Many countries report rapid spread of carbapenem-resistant Acinetobacter baumannii (CRAb) which limits treatment options, with colistin frequently being the last line treatment option. The aim of our study was to evaluate a recently developed rapid...

A DuMond-type crystal spectrometer for synchrotron-based X-ray emission studies in the energy range of 15–26 keV

Jagodziński, Paweł ; Szlachetko, Jakub ; Dousse, Jean-Claude ; Hoszowska, Joanna ; Szlachetko, Monika ; Vogelsang, U. ; Banaś, Dariusz ; Pakendorf, T. ; Meents, A. ; Bokhoven, Jeroen A. van ; Kubala-Kukuś, Aldona ; Pajek, Marek ; Nachtegaal, Maarten

In: Review of Scientific Instruments, 2019, vol. 90, no. 6, p. 063106

The design and performance of a high-resolution transmission-type X-ray spectrometer for use in the 15–26 keV energy range at synchrotron light sources is reported. Monte Carlo X-ray-tracing simulations were performed to optimize the performance of the transmission-type spectrometer, based on the DuMond geometry, for use at the Super X-ray absorption beamline of the Swiss Light Source at...

Laboratory based XAS measurements, electron-induced double K-shell ionization of Sc, Cr and Cu : and, Chemical sensitivity of photoinduced Kʰβ hypersatelite transition in Cr compounds

Zeeshan, Faisal ; Dousse, Jean-Claude (Dir.)

Thèse de doctorat : Université de Fribourg, 2017 ; no. 2052.

Cette thèse de doctorat contient trois différents projets qui appartiennent aux domaines de la physique atomique des couches profondes et de la spectroscopie de rayons X en haute résolution. Le premier projet concerne l’étude des spectres d’absorption (XAS) K et L de quelques éléments de transition 3d, 4d et 5d. Les mesures ont été réalisées à Fribourg avec le spectromètre à...

Determination of conduction and valence band electronic structure of anatase and rutile TiO 2

SZLACHETKO, JAKUB ; MICHALOW-MAUKE, KATARZYNA ; NACHTEGAAL, MAARTEN ; SÁ, JACINTO

In: Journal of Chemical Sciences, 2014, vol. 126, no. 2, p. 511-515

Persistent current of relativistic electrons on a Dirac ring in presence of impurities

Ghosh, Sumit ; Saha, Arijit

In: The European Physical Journal B, 2014, vol. 87, no. 8, p. 1-7

Scatter Characterization and Correction for Simultaneous Multiple Small-Animal PET Imaging

Prasad, Rameshwar ; Zaidi, Habib

In: Molecular Imaging and Biology, 2014, vol. 16, no. 2, p. 199-209

Anisotropic magnetic excitations and incipient N\’eel order in $\mathrm{Ba}{({\mathrm{Fe}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x})}_{2}{\mathrm{As}}_{2}$

Garcia, Fernando A. ; Ivashko, Oleh ; McNally, Daniel E. ; Das, Lakshmi ; Piva, Mario M. ; Adriano, C. ; Pagliuso, Pascoal G. ; Chang, Johan ; Schmitt, Thorsten ; Monney, Claude

In: Physical Review B, 2019, vol. 99, no. 11, p. 115118

It is currently understood that high temperature superconductivity (SC) in the transition metal (M) substituted iron arsenides Ba(Fe1−xMx)2As2 is promoted by magnetic excitations with wave vectors (π,0) or (0,π). It is known that while a small amount of Co substitution lead to SC, the same does not occur for Mn for any value of x. In this work, magnetic excitations in the iron arsenides ...

Comparative study of nonequilibrium insulator-to-metal transitions in electron-phonon systems

Sayyad, Sharareh ; Žitko, Rok ; Strand, Hugo U. R. ; Werner, Philipp ; Golež, Denis

In: Physical Review B, 2019, vol. 99, no. 4, p. 045118

We study equilibrium and nonequilibrium properties of electron-phonon systems described by the Hubbard-Holstein model using dynamical mean-field theory. In equilibrium, we benchmark the results for impurity solvers based on the one-crossing approximation and slave-rotor approximation against non-perturbative numerical renormalization group reference data. We also examine how well the...