Set Electronic Temperature

Message

robsimps · #1 Post by **robsimps** » Fri Feb 14, 2014 9:27 pm

For a ground state relaxed crystallographic structure, I would like to alter the electronic temperature and study the effect on the properties of the crystal. How should I do this?

I have read that the Sigma parameter can be used to change the electronic temperature but I understand that it simply broadens distribution of temperatures around a mean temperature. I actually want to increase the mean temperature.

Thank you and I look forward to your replies.

kambiz · #2 Post by **kambiz** » Tue Mar 04, 2014 2:39 am

Hi,

To me your question is a bit vague. Do you want to see the effect of temperature on the crystal structure or the effect of sigma?

Cheers

paulfons · #3 Post by **paulfons** » Thu Mar 20, 2014 9:10 am

I think his question is clear as he explicitly says electronic temperature. To change electronic occupancies you should use the keywords ISMEAR and SIGMA. If you set ISMEAR to -1, you can, for example, use a Fermi-Dirac distribution where ISMEAR specifies the energy width. See page 143 in the VASP PDF manual for details. One can also use the card FERWE to specify the occupation numbers (nor both band and k points) as well. A final alternative is to use NELEC and change the number of electrons. VASP will add appropriate charged jellium to ensure that the system remains charge neutral.
<span class='smallblacktext'>[ Edited Sun Apr 20 2014, 07:11AM ]</span>