[Wien] Accurate calculation of small band gaps

[tran at theochem.tuwien.ac.at]

Hi,

What do you mean by "as accurate as possible" and "accuracy"?
Is it about the convergence of the band gap value with respect
to the parameters of the calculations like RK? Or is it about
reproducing the experimental value?

In general, the DFT and GW errors (with respect to experiment) for the
band gap is at least 10 times larger than 10 meV. Some literature:
https://pubs.acs.org/doi/abs/10.1021/acs.jpca.7b02882

FT

On Thursday 2018-09-13 13:13, 薄祥??? wrote:

>Date: Thu, 13 Sep 2018 13:13:39
>From: 薄祥??? <bxy1202 at 126.com>
>Reply-To: A Mailing list for WIEN2k users <wien at zeus.theochem.tuwien.ac.at>
>To: "wien at zeus.theochem.tuwien.ac.at" <wien at zeus.theochem.tuwien.ac.at>
>Subject: [Wien] Accurate calculation of small band gaps
>
>Dear Dr. P. Blaha and Wien2k users，
>
>I am learning WIEN2K and trying to calculate a material with a small gap
>about 10 meV. We want to get the value of the gap to be as accurate as
>possible and we have tested the convergence of K-mesh,  the value of the gap
>barely changed with the increase of K-mesh. The difference between our
>calculated results of RK=7 and RK=9 are also very small, while our
>convergence accuracy is also very high. Are there other parameters that can
>be set to increase the accuracy of the calculation? It will be also great if
>you can tell us any example about density-functional calculation
>successfully predicts the band gap around 10 meV.  So that we can take that
>as the benchmark to test. We can also cite that reference in our future
>publications.
>
>Thank you,
>Xiangyan Bo
>
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