Dielectric Constant with Local Field Effect

[sukhito teh]

Dear developers,
From what I understand, the dielectric constant obtained from OpticalSpectrum currently does not account for local field effects, rendering it unsuitable for calculating the dielectric properties of 2D materials. I have observed that QATK now offers GW calculations, and I am curious whether the dielectric tensor involved in GW calculation takes local field effects into consideration. If so, is it possible to save these values for further use?

Thank you for your attention to this matter.

Best Regards,
Sukhito Teh

[Brecht]

Dear Sukito,

that is a good question and we have considered it. The problem is that the GW implementation we have right now works from imaginary time to imaginary frequency. So we have the full dielectric constant with local field effects, but it is in on the imaginary frequency axis, and not on the real one, which is probably what you are interested in. We have experimented a bit with analytically continuing the so obtained dielectric constant to the real axis but the results were not that good. We might revisit this in the future though.

We are currently in the process of improving our OpticalSpectrum with some parts of the GW code to make it more correct when running with non-local hybrid functionals like HSE06. This update should be in the next release W-2024.09.

Kind regards,

Brecht

[sukhito teh]

Thank you for the reply! I am looking forward to the new feature!