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Université de Fribourg

Two-dimensional inversion of wideband spectral data from the capacitively coupled resistivity method – first applications in periglacial environments

Mudler, Jan ; Hördt, Andreas ; Przyklenk, Anita ; Fiandaca, Gianluca ; Maurya, Pradip Kumar ; Hauck, Christian

In: The Cryosphere, 2019, vol. 13, no. 9, p. 2439–2456

The DC resistivity method is a common tool in periglacial research because it can delineate zones of large resistivities, which are often associated with frozen water. The interpretation can be ambiguous, however, because large resistivities may also have other causes, like solid dry rock. One possibility to reduce the ambiguity is to measure the frequency-dependent resistivity. At low...

Université de Fribourg

High-harmonic generation in quantum spin systems

Takayoshi, Shintaro ; Murakami, Yuta ; Werner, Philipp

In: Physical Review B, 2019, vol. 99, no. 18, p. 184303

We theoretically study the high-harmonic generation (HHG) in one-dimensional spin systems. While in electronic systems the driving by ac electric fields produces radiation from the dynamics of excited charges, we consider here the situation where spin systems excited by a magnetic field pulse generate radiation via a time- dependent magnetization. Specifically, we study the magnetic dipole...

Université de Fribourg

First-principles studies of spin-orbital physics in pyrochlore oxides

Shinaoka, Hiroshi ; Motome, Yukitoshi ; Miyake, Takashi ; Ishibashi, Shoji ; Werner, Philipp

In: Journal of Physics: Condensed Matter, 2019, vol. 31, no. 32, p. 323001

The pyrochlore oxides A2B2O7 exhibit a complex interplay between geometrical frustration, electronic correlations, and spin–orbit coupling (SOC), due to the lattice structure and active charge, spin, and orbital degrees of freedom. Understanding the properties of these materials is a theoretical challenge, because their intricate nature depends on material-specific details and quantum...

Université de Fribourg

Scaling of the Fano effect of the in-plane Fe-As phonon and the superconducting critical temperature in ${\mathrm{Ba}}_{1\ensuremath{-}x}{\mathrm{K}}_{x}{\mathrm{Fe}}_{2}{\mathrm{As}}_{2}$

Xu, Bing ; Cappelluti, E. ; Benfatto, Larra ; Mallett, Benjamin P. P. ; Marsik, Premysl ; Sheveleva, Evgeniia ; Lyzwa, Fryderyk ; Wolf, Thomas ; Yang, Rui ; Qiu, X. G. ; Dai, Y. M. ; Wen, H. H. ; Lobo, R. P. S. M. ; Bernhard, Christian

In: Physical Review Letters, 2019, vol. 122, no. 21, p. 217002

By means of infrared spectroscopy, we determine the temperature-doping phase diagram of the Fano effect for the in-plane Fe-As stretching mode in Ba1−xKxFe2As2. The Fano parameter 1=q2, which is a measure of the phonon coupling to the electronic particle-hole continuum, shows a remarkable sensitivity to the magnetic and structural orderings at low temperatures. Most strikingly, at elevated...

Université de Fribourg

Two-dimensional conical dispersion in ${\mathrm{ZrTe}}_{5}$ evidenced by optical spectroscopy

Martino, Edoardo ; Crassee, Iris ; Eguchi, Gaku ; Santos-Cottin, David ; Zhong, R. D. ; Gu, G. D. ; Berger, H. ; Rukelj, Zoran ; Orlita, M. ; Homes, Chris C. ; Akrap, Ana

In: Physical Review Letters, 2019, vol. 122, no. 21, p. 217402

Zirconium pentatelluride was recently reported to be a 3D Dirac semimetal, with a single conical band, located at the center of the Brillouin zone. The cone’s lack of protection by the lattice symmetry immediately sparked vast discussions about the size and topological or trivial nature of a possible gap opening. Here, we report on a combined optical and transport study of ZrTe5, which...

Consortium of Swiss Academic Libraries

Relativistic lattice kinetic theory: Recent developments and future prospects

Succi, S. ; Mendoza, M. ; Mohseni, F. ; Karlin, I.

In: The European Physical Journal Special Topics, 2014, vol. 223, no. 11, p. 2177-2188