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 2019-05-29 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 temperatures in the paramagnetic tetragonal state we observe a linear correlation between 1=q2 and the superconducting critical temperature Tc. Based on theoretical calculations and symmetry considerations, we identify the relevant interband transitions that are coupled to the Fe-As mode. In particular, we show that a sizable xy orbital component at the Fermi level is fundamental for the Fano effect and, thus, possibly also for the superconducting pairing. application/pdf https://folia.unifr.ch/global/documents/307997 https://folia.unifr.ch/documents/307997/files/ber_sfe.pdf https://folia.unifr.ch/documents/307997/files/ber_sfe_sm.pdf eng info:eu-repo/semantics/altIdentifier/doi/10.1103/PhysRevLett.122.217002 info:eu-repo/semantics/openAccess License undefined Physical Review Letters. - 2019, vol. 122, no. 21, p. 217002 info:eu-repo/classification/udc/53 Scaling of the Fano effect of the in-plane Fe-As phonon and the superconducting critical temperature in ${\mathrm{Ba}}_{1\ensuremath{-}x}{\mathrm{K}}_{x}{\mathrm{Fe}}_{2}{\mathrm{As}}_{2}$ http://purl.org/coar/resource_type/c_6501