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Université de Fribourg

Electronic structure beyond the generalized gradient approximation for ${\mathrm{Ni}}_{2}\mathrm{MnGa}$

Baigutlin, D. R. ; Sokolovskiy, V. V. ; Miroshkina, O. N. ; Zagrebin, M. A. ; Nokelainen, J. ; Pulkkinen, Aki ; Barbiellini, B. ; Pussi, K. ; Lähderanta, E. ; Buchelnikov, V. D. ; Zayak, A. T.

In: Physical Review B, 2020, vol. 102, no. 4, p. 045127

The stability of the nonmodulated martensitic phase, the austenitic Fermi surface, and the phonon dispersion relations for ferromagnetic Ni2MnGa are studied using density functional theory. Exchange-correlation effects are considered with various degrees of precision, starting from the simplest local spin density approximation (LSDA), then adding corrections within the generalized gradient...

Université de Fribourg

Ab initio description of the ${\mathrm{Bi}}_{2}{\mathrm{Sr}}_{2}{\mathrm{CaCu}}_{2}{\mathrm{O}}_{8+\ensuremath{\delta}}$ electronic structure

Nokelainen, Johannes ; Lane, Christopher ; Markiewicz, Robert S. ; Barbiellini, Bernardo ; Pulkkinen, Aki ; Singh, Bahadur ; Sun, Jianwei ; Pussi, Katariina ; Bansil, Arun

In: Physical Review B, 2020, vol. 101, no. 21, p. 214523

Bi-based cuprate superconductors are important materials for both fundamental research and applications. As in other cuprates, the superconducting phase in the Bi compounds lies close to an antiferromagnetic phase. Our density functional theory calculations based on the strongly-constrained-and- appropriately-normed exchange correlation functional in ...

Université de Fribourg

Unconventional free charge in the correlated semimetal Nd2Ir2O7

Wang, K. ; Xu, Bing ; Rischau, C. W. ; Bachar, N. ; Michon, B. ; Teyssier, J. ; Qiu, Y. ; Ohtsuki, T. ; Cheng, Bing ; Armitage, N. P. ; Nakatsuji, S. ; van der Marel, D.

In: Nature Physics, 2020, p. -

Nd2Ir2O7 is a correlated semimetal with the pyrochlore structure, in which competing spin–orbit coupling and electron–electron interactions are believed to induce a time- reversal symmetry-broken Weyl semimetal phase characterized by pairs of topologically protected Dirac points at the Fermi energy1,2,3,4. However, the emergent properties in these materials are far from clear, and exotic...

Université de Fribourg

Free-standing graphene oxide mid-infrared polarizers

Zheng, Xiaorui ; Xu, Bing ; Li, Shuo ; Lin, Han ; Qiu, Ling ; Li, Dan ; Jia, Baohua

In: Nanoscale, 2020, vol. 12, no. 21, p. 11480–11488

Mid-infrared (MIR) represents a crucial spectral region for applications in spectroscopy, sensing, imaging, security and industry screening, owing to the strong characteristic vibrational transitions of many important molecules. However, the current MIR compatible materials are fragile, hazardous, and costly, which hampers the performance of MIR devices. Here, we developed a versatile...

Université de Fribourg

Optical conductivity of the type-II Weyl semimetal TaIrTe4

Mardelé, F. Le ; Santos-Cottin, D. ; Martino, E. ; Semeniuk, K. ; David, S. Ben ; Orbanić, F. ; Novak, Mark ; Rukelj, Z. ; Homes, C. C. ; Akrap, Ana

In: Physical Review B, 2020, vol. 102, no. 4, p. 045201

TaIrTe4 is an example of a candidate Weyl type-II semimetal with a minimal possible number of Weyl nodes. Four nodes are reported to exist in a single plane in k space. The existence of a conical dispersion linked toWeyl nodes has yet to be shown experimentally. Here, we use optical spectroscopy as a probe of the band structure on a low-energy scale. Studying optical conductivity allows us to...

Haute Ecole pédagogique Fribourg

Grounding Social Foundations for Integrated Assessment Models of Climate Change

Mathias, Jean-Denis ; Debeljak, Marko ; Deffuant, Guillaume ; Diemer, Arnaud ; Dierickx Florian ; Donges, Jonathan F. ; Gladkykh, Ganna ; Heitzig, Jobst ; Holtz, Georg ; Obergassel, Wolfgang ; Pellaud, Francine ; Sanchez, Angel ; Trajanov, Aneta ; Videira, Nuno

In: AGU Advancing Earth and Space Science, 2020, vol. 8, no. 7, p. 1-5

Integrated assessment models (IAMs) are commonly used by decision makers in order to derive climate policies. IAMs are currently based on climate‐economics interactions, whereas the role of social system has been highlighted to be of prime importance on the implementation of climate policies. Beyond existing IAMs, we argue that it is therefore urgent to increase efforts in the integration of...

Haute Ecole pédagogique Fribourg

"FABuleux objets"

Pellaud, Francine ; Heinzen, Samuel ; Marbacher, Vincent ; Brumeau, Quentin ; Quartenoud, Aïcha ; Sautaux, Matthieu

In: Ecole changer de cap!, 2019, p. 1-7

Un projet interdisciplinaire mêlant éducation au développement durable, éthique et travaux manuels : que peut-il apporter aux étudiants, futurs enseignants primaires ?