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

Robustness of the charge-ordered phases in ${\mathrm{IrTe}}_{2}$ against photoexcitation

Monney, Claude ; Schuler, A. ; Jaouen, T. ; Mottas, Marie-Laure ; Wolf, Thomas ; Merz, M. ; Muntwiler, Matthias ; Castiglioni, L. ; Aebi, Philipp ; Weber, F. ; Hengsberger, M.

In: Physical Review B, 2018, vol. 97, no. 7, p. 075110

We present a time-resolved angle-resolved photoelectron spectroscopy study of IrTe2, which undergoes two first-order structural and charge-ordered phase transitions on cooling below 270 K and below 180 K. The possibility of inducing a phase transition by photoexcitation with near-infrared femtosecond pulses is investigated in the charge-ordered phases. We observe changes of the spectral...

Université de Fribourg

Clocking the onset of bilayer coherence in a high-${T}_{c}$ cuprate

Baldini, Edoardo ; Mann, Andreas ; Mallett, Benjamin P. P. ; Arrell, Christopher ; Mourik, Frank van ; Wolf, Thomas ; Mihailovic, Dragan ; Tallon, Jeffrey L. ; Bernhard, Christian ; Lorenzana, José ; Carbone, Fabrizio

In: Physical Review B, 2017, vol. 95, no. 2, p. 024501

In cuprates, a precursor state of superconductivity is speculated to exist above the critical temperature TC. Here we show via a combination of far-infrared ellipsometry and ultrafast broadband optical spectroscopy that signatures of such a state can be obtained via three independent observables in an underdoped sample of NdBa2Cu3O6+δ. The pseudogap correlations were disentangled from the...