polar 2d materials

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nprot
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Joined: Mon Oct 30, 2017 4:13 pm
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polar 2d materials

Post by nprot »

Hi,

QE/EPW currently does not use a truncated Coulomb potential for treating 2d materials. As such, is it correct to use the flag lpolar for the calculation of self-energies for polar 2d materials? I find that when lpolar is true for monolayer MoS2, the electronic scattering rates come out to be three orders of magnitude higher than published results in literature. Setting lpolar to false gives reasonable results.

On a related note, I found that the flag system_2d does not make any difference to the result.

Best regards

sponce
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Re: polar 2d materials

Post by sponce »

Dear nprot,

It is correct, there are no Coulomb truncations at the moment.

You have to use the polar flag otherwise the Wannier interpolation will be very wrong close to the zone center.

The flag system_2d is indeed inactive at the moment for that part of the code.

What you would have to do at the moment is to increase the vacuum layer until convergence (this can be very large due to the 1/r interaction between replicas).

Best,
Samuel
Prof. Samuel Poncé
Chercheur qualifié F.R.S.-FNRS / Professeur UCLouvain
Institute of Condensed Matter and Nanosciences
UCLouvain, Belgium
Web: https://www.samuelponce.com

nprot
Posts: 2
Joined: Mon Oct 30, 2017 4:13 pm
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Re: polar 2d materials

Post by nprot »

Thank you.

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