The interaction between electrons and nuclei in molecules and solids has a profound impact on their properties. It affects aspects like conductivity, energy storage, phase transitions, and superconductivity. Recently, a team led by ICREA Prof. Jens Biegert at ICFO has introduced a groundbreaking technique for studying these interactions in real-time using attosecond soft X-ray spectroscopy.
This method involves using extremely short bursts of soft X-rays with photon energies covering the water-window range. By employing high-order harmonic generation with a powerful short-wavelength infrared pulse, the team achieved the generation of a remarkably short 165 attosecond pulse with photon energies up to 600 eV. When directed at a sample, these high-energy X-ray photons can excite electrons in the K-shell or L-shell to unoccupied or continuum states.
Attosecond soft X-ray absorption spectroscopy is a formidable tool that enables researchers to simultaneously explore both electronic and structural aspects of materials. This innovation allows for capturing atomic-scale snapshots with unprecedented attosecond precision, offering deep insights into the intertwined behaviors of electrons and phonons. Understanding these nonequilibrium and correlated interactions is crucial for advancing condensed matter science and designing intelligent materials with tailored properties, such as efficient light harvesting, energy storage, and information processing.
The findings from this study have been published in the Ultrafast Science journal.