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Université de Fribourg

Ultrafast coupled charge and spin dynamics in strongly correlated NiO

Gillmeister, Konrad ; Golež, Denis ; Chiang, Cheng-Tien ; Bittner, Nikolaj ; Pavlyukh, Yaroslav ; Berakdar, Jamal ; Werner, Philipp ; Widdra, Wolf

In: Nature Communications, 2020, vol. 11, no. 1, p. 4095

Charge excitations across an electronic band gap play an important role in opto- electronics and light harvesting. In contrast to conventional semiconductors, studies of above-band-gap photoexcitations in strongly correlated materials are still in their infancy. Here we reveal the ultrafast dynamics controlled by Hund’s physics in strongly correlated photoexcited NiO. By combining...

Université de Fribourg

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....

Université de Fribourg

Magnetic-field effects on one-dimensional Anderson localization of light

Schertel, Lukas ; Irtenkauf, Oliver ; Aegerter, Christof M. ; Maret, Georg ; Aubry, Geoffroy J.

In: Physical Review A, 2019, vol. 100, no. 4, p. 043818

Transport of coherent waves in multiple-scattering media may exhibit fundamental, nonintuitive phenomena such as halt of diffusion by disorder called Anderson localization. For electromagnetic waves, this phenomenon was observed only in one and two dimensions so far. However, none of these experiments studied the contribution of reciprocal paths nor their manipulation by external fields. In...

Université de Fribourg

Coupling of electronic and nuclear motion in a negative ion resonance: Experimental and theoretical study of benzene

Allan, Michael ; Čurík, Roman ; Čársky, Petr

In: The Journal of Chemical Physics, 2019, vol. 151, no. 6, p. 064119

We present calculated and measured elastic and vibrational excitation cross sections in benzene with the objective to assess the reliability of the theoretical method and to shed more light on how the electronic motion of the incoming electron is coupled with the nuclear motion of the vibrations. The calculation employed the discrete momentum representation method which involves solving the...

Université de Fribourg

The structural colors of photonic glasses

Schertel, Lukas ; Siedentop, Lukas ; Meijer, Janne-Mieke ; Keim, Peter ; Aegerter, Christof M. ; Aubry, Geoffroy J. ; Maret, Georg

In: Advanced Optical Materials, 2019, p. 1900442

The color of materials usually originates from a combination of wavelength‐dependent absorption and scattering. Controlling the color without the use of absorbing dyes is of practical interest, not only because of undesired bleaching properties of dyes but also regarding minimization of environmental and health issues. Color control without dyes can be achieved by tuning the material's...

Consortium of Swiss Academic Libraries

Integer and fractional quantum Hall effect in a strip of stripes

Klinovaja, Jelena ; Loss, Daniel

In: The European Physical Journal B, 2014, vol. 87, no. 8, p. 1-16

Université de Fribourg

Dissociative electron attachment and electronic excitation in Fe(CO)5

Allan, Michael ; Lacko, M. ; Papp, P. ; Matejčík, Š. ; Zlatar, Matija ; Fabrikant, Ilya I. ; Kočišek, J. ; Fedor, Juraj

In: Physical Chemistry Chemical Physics, 2018, vol. 20, no. 17, p. 11692–11701

In a combined experimental and theoretical study we characterize dissociative electron attachment (DEA) to, and electronically excited states of, Fe(CO)5. Both are relevant for electron-induced degradation of Fe(CO)5. The strongest DEA channel is cleavage of one metal–ligand bond that leads to production of Fe(CO)4−. High- resolution spectra of Fe(CO)4− reveal fine structures at the...

Consortium of Swiss Academic Libraries

A dynamic high-resolution simulation of 2-D elastic-plastic crack problems

Giese, G. ; Fey, M.

In: Computational Mechanics, 2004, vol. 34, no. 6, p. 503-509

Consortium of Swiss Academic Libraries

Experiments with polarized 3He at MAMI

Rohe, D.

In: The European Physical Journal A - Hadrons and Nuclei, 2006, vol. 28, p. 29-38