Band Gap for ICHARG = 2

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ahsan_javed
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Band Gap for ICHARG = 2

#1 Post by ahsan_javed » Tue Nov 21, 2023 2:02 pm

While doing band structure calculations with SCAN FUNCTIONAL AND ICHARG = 11, the error pops up

“ICHARG>9 is currently not supported for meta-GGA functionals. In case you want to calculate band structure with a meta-GGA, use the same method as proposed for hybrid functionals”

i tried to do it in hybrid calculations method but error persisted. So I did it for ICHARG=2 and it works. Band gap is in comparison with literature.

Question is: SCF based band structure calculation is not an issue?

fabien_tran1
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Re: Band Gap for ICHARG = 2

#2 Post by fabien_tran1 » Tue Nov 21, 2023 2:44 pm

Hi,

To do a band structure calculation with a meta-GGA functional you need to follow the steps 1 to 5 explained here:
https://www.vasp.at/wiki/index.php/Band ... unctionals
Note that:
-What is mentioned about HFALPHA and HFRCUT concerns only hybrid functionals, thus ignore it.
-For step 2, you can choose either option 1 or 2, both should provide the same results (as an exercise you can try both).
-Do not set any value for ICHARG in INCAR. With the procedure mentioned above, the default value should be used.

ahsan_javed
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Re: Band Gap for ICHARG = 2

#3 Post by ahsan_javed » Fri Dec 01, 2023 12:50 pm

I tried but same error halts the calculations again.

and if ICHARG is not to set manually and by default it is taken to be ICHARG = 2, for example, then isn't what i am doing (stated above) is correct.?

fabien_tran1
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Re: Band Gap for ICHARG = 2

#4 Post by fabien_tran1 » Mon Dec 04, 2023 10:24 am

That is difficult to guess what is the problem. You need to describe in detail and exactly what procedure you followed. Also, according to the posting guidelines (https://www.vasp.at/forum/viewtopic.php?t=17928), you need to provide the input files (at least INCAR).

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