Category Archives: electron-phonon coupling

Exciton-phonon coupling tutorial

A new tutorial on exciton-phonon coupling in Yambo is available. In this tutorial we will show how to generate exciton-phonon matrix elements and calculate phonon-assisted absorption and emission. In the last part of the tutorial the exciton-phonon matrix elements will be used to calculate exciton life-time. The tutorial is based on a preliminary version of… Read More

Theory of phonon-assisted luminescence

In this presentation I present the theory of phonon-assisted luminescence, in terms of non-equilibrium  Green’s functions and time-dependent perturbation theory. We derived a simple formule for light emission in the limit of low excited carriers including excitonic effects and then included coupling with phonons by time-dependent perturbation theory. This approach is then applied to the… Read More

New poster on GW renormalization of the electron-phonon interaction

Here my new poster that I will present to the PSI-K conference on the GW renormalization of the electron-phonon interaction. In this poster I summarize results from different group that used GW approximation to correct the electron-phonon coupling obtained from the Kohn-Sham Hamiltonian. Thanks to these corrections it was possible to reproduce and predict different… Read More

Exploring approximations to the GW self-energy ionic gradients

A new paper is out on the different approximation in  GW  for the electron-phonon couping matrix elements. In particular we tested two approximation the static screening (COHSEX) and the constant screening respect to the phonon displacement. We found that the first approximation miserably fails to reproduce the G0W0 results while the second introduce a negligible… Read More

GW renormalization of the electron-phonon coupling

My new presentation on the “GW renormalization of the electron-phonon coupling” is available online. This is the talk I gave to the “Correlation Meeting 2014” organized by Pina Romaniello. In this presentation I show that GW corrections are important not only for band structure and energy levels but they also renormalise the electron-phonon matrix elements…. Read More