FisMat2017 - Submission - View

Abstract's title: Pump and probe experiments from first principles
Submitting author: Davide Sangalli
Affiliation: Division of Ultrafast Processes in Materials (FLASHit), CNR-ISM, Monterotondo, Italy
Affiliation Address: Istituto di Struttura della Materia (ISM) Consiglio Nazionale delle Ricerche (CNR) Via Salaria Km 29.3, CP 10, 00016 Monterotondo Stazione, Italy
Country: Italy
Oral presentation/Poster (Author's request): Oral presentation
Other authors and affiliations: AUTHORS: Davide Sangalli (1,5), Alejandro Molina Sancez (2,5), Alexandre Morlet (3), Ludger Wirtz (3,5), Enrico Perfetto (1), Gianluca Stefanucci (4), Andrea Marini (1,5) ------ AFFILIATIONS: (1) Division of Ultrafast Processes in Materials (FLASHit), CNR-ISM, Monterotondo, Italy (2) Materials Science Institute (ICMUV), University of Valencia, Spain (3) Physics and Materials Science Research Unit, University of Luxembourg, Luxembourg (4) Physics Department, University of Rome Tor Vergata, Italy (5) European Theoretical Spectroscopy Facility
Abstract

The development of ultra-short laser pulses has opened the opportunity to investigate the dynamics of electrons on the fs time-scale (1 fs=10-15 seconds). After the photo-excitation with such lasers pulses, electrons are in a regime which is highly out-of-equilibrium. Here we present a novel numerical approach, based on the merging of the out-of-equilibrium Green's function method with the ab-initio, Density-Functional-Theory, to describe this regime in semi-conductors.

Silicon is used as reference material to show the physical process involved. The simulations are also compared with recent two photon photo-emission and transient-reflectivity measurements. Moreover we consider MoS2 monolayer and discuss transient absorption and transient Kerr in the system, computed with the same approach. Also in this case the simulations are also compared with recent transient-absorption and transient-kerr measurements. We show that we capture both the frequency shape and the time decay of both transient absorption and kerr signal.