Single-layer monochalcogenides have recently attracted much attention in the scientific community for their strong non-linear response, in particular the second harmonic generation(SHG). The origin of this strong response is still debated. A strong mismatch exist between theory and experiments. In order to clarify this issue, in this work we performed first-principles calculation of linear and… Read More
Yambo is an open source project aimed at studying excited state properties of condensed matter systems from first principles using many-body methods. As input, yambo requires ground state electronic structure data as computed by density functional theory codes such as Quantum-Espresso and Abinit.Yambo’s capabilities include the calculation of linear response quantities (both independent-particle and including… Read More
We are pleased to announce the opening of a post at the level of Senior Lecturer / Associate Professor at Aix-Marseille University in spring 2019. We are looking for a theoretician in condensed matter with significant experience in electronic structure calculations and atomistic simulations (e.g. DFT, TD-DFT, ab-initio methods, Monte Carlo sampling, molecular dynamics)…. Read More
This year I was invited to give two lectures at the school on “Theoretical Spectroscopy” organized by F. Sottile, V. Olevano and G. Rignanese. I will present two lectures on “Non-linear approaches to TDDFT :: non perturbative real-time” and “Bethe-Salpeter Equation in real time” and a tutorial on the Lumen code. All the lectures are… Read More
Luminescence of hexagonal boron nitride (hBN) has puzzled researchers for long time. In standard solid state physics textbooks direct band gap semiconductors are considered efficient light emitters while indirect ones are regarded as inefficient. Hexagonal boron nitride seems to defy this rule. In fact hBN emits light in the ultraviolet with an efficient comparable to… 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
Our Prace research project OPTEL2D “Opto-electronic properties of 2D Transition Metal Dichalcogenides with DFT and post-DFT simulations” has been accepted, and we got 49.5 million core hours on Marconi – KNL. Here the project description: “Two-dimensional (2D) and layered materials possess novel combinations of electronic and optical properties and thus present a unique… Read More
The Interdisciplinary Nanoscience Center of Marseille (CINaM), a laboratory working under the joint authority of the Centre National de la Recherche Scientifique (CNRS)and the Aix-Marseille University (AMU), invites applications for a full-time endowed position at a Professor level. The research activity will be developed in the Theory and Computer Simulation department, in relation with experimental… Read More
In this work we combine tight-binding calculations of the two-photon transition probability with sophisticated ab-initio real-time Bethe-Salpeter simulations of the two-photon resonance third-order susceptibility. This combination is a unique feature of this work: on the one hand the tight-binding calculations allow us to identify the symmetry properties of the excitons, on the other hand the… Read More
My collaborator Myrta Grüning gave a very interesting talk about the role of excitons in non-linear optical properties of 2D materials at the OSI 2017 conference. She discusses both second and third harmonic generation in low dimensional nanostructures. Slides of her talk are available here .