Over the last few years the field of ultrafast spectroscopy has opened new frontiers in the study of correlated materials. For instance, extension in the time-resolved regime of Angle-resolved photoemission spectroscopy (TR-ARPES), has revealed to be a powerful technique to study of unconventional superconductivity.
In the first part of this contribution I will present our TR-ARPES measurements on the cuprate Bi2Sr2CaCu2O8+δ. By employing a pulse of duration comparable to the timescales of the superconducting state we demonstrate the capability of the pump pulse to manipulate the phase fluctuations [1] and the electron-bosons coupling [2] independently of the pairing.
More recently, Free Electrons Lasers (FEL) have developed as a powerful tool to perform ultrafast spectroscopy in the XUV, Soft- and Hard- X-ray. In the second part of the talk I will introduce the experimental endstation Furka of the soft x-ray branch (Athos) of the SwissFEL [3]. The Furka experimental endstation will be dedicated to time-resolved Resonant Inelastic and Elastic X-ray Scattering (tr-RIXS and tr-REXS) as well as X-Ray Diffraction (tr-XRD) in the soft X-ray regime. In particular, tr-RIXS opens new scientific opportunities thanks to its unique capability to probe the energy and momentum time-evolution of elementary excitations in solids.
[1] F. Boschini, E. H. da Silva Neto, E. Razzoli, et al., “Collapse of superconductivity in cuprates via ultrafast quenching of phase coherence” Nature Materials 17, 416(2018).
[2] E. Razzoli*, F. Boschini* et al., “Ultrafast reduction of electron-boson kink induced by phase coherence loss in cuprates” in submission.
[3] R. Follath1, U. Flechsig, U. H. Wagner, and L. Patthey, Optical design of the Athos beamlines at SwissFEL, AIP Conference Proceedings 2054, 060024 (2019).