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HL: Fachverband Halbleiterphysik
HL 21: 2D Materials II: Electronic Structure, Excitations, etc. (joint session O/CPP/HL)
HL 21.3: Vortrag
Montag, 16. März 2020, 15:30–15:45, WIL C107
Photoinduced band renormalization in the nodal-line semimetal ZrSiSe — •Gianmarco Gatti1, Alberto Crepaldi1, Nicolas Tancogne-Dejean2, Michele Puppin3, Angel Rubio2, Majed Chergui3, and Marco Grioni1 — 1Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland — 2Max Planck Institute for the Structure and Dynamics of Matter and Center for Free-Electron Laser Science, Luruper Chaussee 149, 22761 Hamburg, Germany — 3Laboratory of Ultrafast Spectroscopy, ISIC, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
ZrSiSe is a layered material that is classified as a nodal-line semimetal. Its low-energy bandstructure is composed by linearly dispersing surface and bulk bands whose crossing points creates a one-dimensional contour in the momentum space with vanishing density of states close to the Fermi level. We investigate its equilibrium and out-of-equilibrium electronic structure by the means of angle- and time-resolved photoemission spectroscopy and compare the results with ab initio calculations. Our analysis indicates that the dispersion of the Dirac quasiparticle can be correctly reproduced by density functional theory with the inclusion local and non-local electronic correlations. Moreover, we observe a transient renormalization of the bands velocity above the Fermi level under the photoexcitation produced by ultrashort infrared pulses. We associate the microscopic origin of this effect to the increased screening of the non-local Coulomb interaction due to the presence of high-energy and non-thermalized carriers.