Yambo Community Forum

Hi all,
I'm very interested in Yambo's exciton-phonon realization.

Now I’m trying to reproduce the results of Prof. Marini’s paper titled “ab initio finite-temperature exciton”. For silicon, by following the tutorial on Yambo’s website, I have nicely reproduced the finite-temperature optical absorption spectra.

But for h-BN, after including exciton-phonon interactions the spectra redshift compared with frozen-atom BSE one as shown in the attached figure, which is opposite to Prof. Marini’s result.

I’m confused a lot. Is there something to be careful when doing calculations on exciton-phonon interactions? Below is some computational details,
LDA indirect bandgap: 4.03 eV, direct bandgap: 4.51 eV
For the electron-phonon calculations, I used 6*6*2 k-grid in scf and nscf calculation and 50 random q points in ph calculations.
For the bse calculations, I used 18*18*6 k-grid.

I also attached some input and output files. Could you please help me?

Thank you very much!

Best regards,
Xiaowei

Dear Xiaowei

your results seem correct to me, instead, the behavior in the Marini paper is very strange.
Please have a look also to

https://journals.aps.org/prb/pdf/10.110 ... .89.085202

or

https://aip.scitation.org/doi/abs/10.1063/1.4927081

that performed similar calculations on other materials and found results similar to yours
best regards
Claudio Attaccalite

Dear Claudio,
Thank you very much. I will carefully read the two papers.
Best regards
Xiaowei

Dear Xiaowei

another calculation was performed with Yambo on hexagonal boron nitride,

https://arxiv.org/pdf/1811.01695.pdf

you can compare your results with them too

best
Claudio

Dear Claudio
OK, thank you.
Xiaowei