Exciton-phonon coupling and luminescence: Difference between revisions
No edit summary |
No edit summary |
||
| Line 21: | Line 21: | ||
<span style="color:red">GkkpExpand</span> # Expand the gkkp in the whole BZ | <span style="color:red">GkkpExpand</span> # Expand the gkkp in the whole BZ | ||
#UseQindxB # Use qindx_B to expand gkkp (for testing purposes) | #UseQindxB # Use qindx_B to expand gkkp (for testing purposes) | ||
if everything worked fine in the log you will find: | |||
.... | |||
<---> :: Uniform sampling :yes | |||
<---> :: Symmetry expanded :yes | |||
..... | |||
== References == | == References == | ||
Revision as of 09:49, 21 February 2022
This tutorial works only with Yambo version > 6.x
The exciton-phonon part of Yambo does not support symmetries yet!!!
This an advanced tutorial, in order to calculate exciton-phonon coupling and phonon-assisted absorption/emission you need a deep knowledge of the theory and of the Yambo code.
In this tutorial we will calculate phonon-assisted absorption and luminescence including the scattering between exciton and phonon.[1][2][3]
We will consider as example bulk silicon. Notice that parameters of the present tutorial are not at convergence, but are just as a possible example.
The tutorial includes several steps and the calculations can be quite expensive.
Electron-phonon matrix elements:
First of all we calculate electron-phonon matrix elements as explained in the section: Electron-phonon matrix elements but in the last passage of the tutorial we expand the electron-phonon matrix elements in all the Brillouin Zone. In order to do so, when we read the electron-phonon matrix elements from QE with the command ypp_ph -g g we turn on the flag GkkpExpand
gkkp # [R] gkkp databases gkkp_db # [R] GKKP database #GkkpReadBare # Read the bare gkkp DBsPATH= "../elph_dir/" # Path to the PW el-ph databases PHfreqF= "none" # PWscf format file containing the phonon frequencies PHmodeF= "none" # PWscf format file containing the phonon modes GkkpExpand # Expand the gkkp in the whole BZ #UseQindxB # Use qindx_B to expand gkkp (for testing purposes)
if everything worked fine in the log you will find:
.... <---> :: Uniform sampling :yes <---> :: Symmetry expanded :yes .....
References
- ↑ Theory of phonon-assisted luminescence in solids: Application to hexagonal boron nitride, E. Cannuccia, B. Monserrat and C. Attaccalite, Phys. Rev. B 99, 081109(R) (2019)
- ↑ Exciton-Phonon Coupling in the Ultraviolet Absorption and Emission Spectra of Bulk Hexagonal Boron Nitride, F. Paleari et al. PRL 122, 187401(2019)
- ↑ Exciton-Phonon Interaction and Relaxation Times from First Principles, Hsiao-Yi Chen, Davide Sangalli, and Marco Bernardi,Phys. Rev. Lett. 125, 107401(2020)