Publication
We use time- and angle-resolved photoemission spectroscopy with sub-30-fs extreme-ultraviolet pulses to map the time- and momentum-dependent electronic structure of photoexcited 1T-TaS2. This compound is a two-dimensional Mott insulator with charge-density wave ordering. Charge order, evidenced by splitting between occupied subbands at the Brillouin zone boundary, melts well before the lattice responds. This challenges the view of a charge-density wave caused by electron-phonon coupling and Fermi-surface nesting alone, and suggests that electronic correlations play a key role in driving charge order.
Majed Chergui, Marco Grioni, Arnaud Magrez, Helmuth Berger, Philippe Bugnon, Alberto Crepaldi, Luca Moreschini, Simon Karl Moser, Gianmarco Gatti, Serhii Polishchuk
Nicola Marzari, Iurii Timrov, Matteo Cococcioni, Andrea Floris