Ultrafast filling of an electronic pseudogap in photoexcited (LaS) 1.196 VS 2
Résumé
We investigate by angle and time resolved photoemission spectroscopy the unusual insulating state of strongly distorted triangular V slabs in (LaS)1.196VS2. We show that the electronic structure is dominated by the lowest band of the V t2g manifold, which disperses over 0.7 eV and is nearly filled. Hence, (LaS)1.196VS2 is not a Mott insulator. The spectra are strongly temperature dependent, shifting by 100 meV upon cooling to 50 K. The sudden photoexcitation at 50K induces a partial filling of the electronic pseudogap within less than 80 fs. The electronic energy flows into the lattice modes on a comparable timescale. We conclude that a very strong electron-phonon coupling makes this state extremely sensitive to small perturbations of the V clusters distortions.
| Origine | Fichiers produits par l'(les) auteur(s) |
|---|
Loading...