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...

Université de Fribourg

Selection on stability across ecological scales

Borrelli, Jonathan J. ; Allesina, Stefano ; Amarasekare, Priyanga ; Arditi, Roger ; Chase, Ivan ; Damuth, John ; Holt, Robert D. ; Logofet, Dmitrii O. ; Novak, Mark ; Rohr, Rudolf P. ; Rossberg, Axel G. ; Spencer, Matthew ; Tran, J. Khai ; Ginzburg, Lev R.

In: Trends in Ecology & Evolution, 2015, vol. 30, no. 7, p. 417–425

Much of the focus in evolutionary biology has been on the adaptive differentiation among organisms. It is equally important to understand the processes that result in similarities of structure among systems. Here, we discuss examples of similarities occurring at different ecological scales, from predator–prey relations (attack rates and handling times) through communities (food-web structures)...