Ab initio calculations of exciton-phonon coupling in semiconducting systems

 One of the most important lossy mechanisms in solid state systems is the

scattering of excitonic states with phonons, contributing to the degradation

of optoelectronic performance. In this work we report a study of the calculation of exciton lifetimes in transition metal dichalcogenides (TMD) and

other band gap systems. TMD, in particular, are characterized by strong

Coulombic interactions, and as a consequence low screening coefficients.

That gives rise to tightly bound excitons that dominate the optical properties of the material. Phonon-induced interactions between bright and dark

excitonic states influence the coherence times of these systems. By using

a combination of density functional theory and many body perturbation

theory we can extract exciton lifetimes, and phonon linewidths for these

materials.