In this talk I present our new results on sum/difference frequency generation in 2D material. We also discuss the possibility to tune non-linear response using static or ThZ electric fields, you can find the slides of my talk here:SumFrequencyGeneration.odp and the two reference papers here: Sum frequency generation from real-time simulations in two-dimensional crystals MN…. Read More
The Computational School on Electronic Excitations in Novel Materials Using the Yambo Code, introduces participants to post-DFT simulations, in particular many-body perturbation theory (MBPT) approaches and provide training in the calculation of electronic and optical properties of materials. The program will offer theoretical and technical lectures, as well as dedicated hands-on sessions where the students… Read More
In this work we study how different atomic configurations, and electronic correlation modify the exciton dispersion in hexagonal boron nitride. We use two different approaches, ab-initio DFT plus many-body perturbation theory and tight-binding. We found that in the case of AB-stacking electronic correlation inverts the nature of the optical gap, from indirect to direct respect… Read More
New talk for the conference “2D layered materials for opto-electronics: a theoretical/computational perspective” in Rome. In this work we study excitations in hexagonal Boron Nitride that are invisible in linear optical response. We show that these dark states can be measured with other spectroscopic techniques and they play an important roles in the luminescence response… Read More
New paper on excitations in hexagonal Boron-Nitride. Core and low energy electronic excitations have been studied in hexagonal boron nitride by means of angular resolved electron energy loss spectroscopy and theoretical calculations. Paper: Angular resolved electron energy loss spectroscopy in hexagonal boron nitride Poster: Modeling excitons in bulk and single-layer hBN
In this work we studied the C-C defect complex in silicon. We used different approaches in such a way to identity the defect configuration responsible for the strong light emission in irradiated silicon. Our clues point towards a particular configuration, even if we suspect that in a damaged sample different type of complexes could be… Read More
In this work we compare the optical absorption of extended systems calculated starting from the density-density and current-current linear response formalisms within the equilibrium many-body perturbation theory(MBPT). We show how, using the latter, one can incur in errors due to quasiparticle lifetimes, electron-hole interaction or the presence of a Drude tail. These errors are found… Read More
My new talk on Many-Body Perturbation Theory (MBPT) in chemistry is online. If you want to know what MBPT can do in finite systems have a look to this talk. There is an historical introduction and then I discuss different approximations as GW, BSE and present applications in organic chemistry. More recent progresses are presented… Read More
The first draft of my thesis for the accreditation to direct research (Habilitation à Diriger des Recherches) is available online. The thesis covers my studies of the non-linear response in solids and nanostructures by means of real-time simulations. In the thesis I discuss how to couple electrons and external fields by means of Modern Theory… Read More
A new poster on our work on real-time density polarization functional theory. In presence of a time-dependent macroscopic electric field the electron dynamics of dielectrics cannot be described by the time-dependent density only. We present a real-time formalism that has the density and the macroscopic polarization P as key quantities. We show that a simple… Read More