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
In this talk I will discuss luminescence of mono-layer hexagonal boron nitride, taking into account exciton-phonon coupling and the role of substrate. Results are compared with recent experimental measurements.Here the ODP file.
In this new work we study luminescence in monolayer hexagonal boron nitride (m-hBN) using a new ab-initio approach that takes into account the effects of atomic vibrations on the luminescence spectra. We construct the dynamical exciton-phonon self-energy, then use it to perturbatively correct the optical response functions and test this approach on bulk hBN as… Read More
In this seminar I present new thoeretical and exparimental results on hexagonal-boron nitride under isotropic pressure and uni-axial strain. In particalar we focused on the changes in the optical response both absortion and emission. We show how exicton behave under these extreme conditions.The presentation can You can downloaded here: A squashed and squeezed h-BN [ODP]
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
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