Free electron laser-driven ultrafast rearrangement of the electronic structure in Ti

High-energy density extreme ultraviolet radiation delivered by the FERMI seeded free-electron laser has been used to create an exotic nonequilibrium stateöf matter in a titanium sample characterized by a highly excited electron subsystem at temperatures in excessöf 10 eV and a cold solid-density ion lattice. Theöbtained transient state has been investigated through ultrafast absorption spectroscopy across the Ti M2,3-edge revealing a drastic rearrangementöf the sample electronic structure around the Fermi levelöccurringön a time scaleöf about 100 fs.