Category Archives: optical properties

Modeling excitons in bulk and single-layer hBN

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

What is the nature of the C-C complex in silicon? Insights from electronic structure calculations

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

Optical properties of extended systems within a current-current response formalism: tips and tricks

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

Many-body perturbation theory for electronic and optical properties of organic systems

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

My thesis for the Habilitation à Diriger des Recherches

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

New poster on real-time DPFT

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

Optical properties of Cu-chalcogenide photovoltaic absorbers from self-consistent GW and the Bethe-Salpeter equation

We pubblised a new paper1 on the optical properties of Cu-chalcogenide photovoltaic absorbers. In this manuscript we  calculate the optical response of the less studied, but promising, Cu2ZnGe(S,Se)4 compounds, opening the way to predictive calculations of still unknown materials by means of self-consistent GW plus Bethe-Salpeter equations. Moreover in this paper we solved the problem… Read More