# [CP2K:8672] How to calculate Fermi energy of metals?

ashish dabral ashishd... at gmail.com
Wed Feb 8 23:09:25 UTC 2017

```Thanks for your reply Ari. I am looking for the fermi energy from the
bottom of the conduction band. I think what you are referring to is the
work function. Matt has specified the same thing in the next reply. The
information, nonetheless, is useful. Thanks.

On Wednesday, 8 February 2017 23:15:19 UTC+1, Ari Paavo Seitsonen wrote:
>
> Dear Ashish Dabral,
>
>   The only way _I_ know is to calculate a system with surface (well, two,
> slab model) and then align the Fermi energy via the potential in the middle
> of the slab - should be thick enough so that in the middle it is converged
> - and the potential in the middle of the vacuum. So the value of "Fermi
> energy" would be the work function. I guess that one would get the same
> value if one would then take the difference of the potential in the middle
> of the slab and potential in the vacuum, and then uses that after aliging
> the difference between the potential and the Fermi energy in a bulk system.
>
>   With GGA one usually gets too small values of the work function if I
> remember correctly (self-interaction/asymptotics), by about 0.5-1 eV
> depending on the material.
>
>     Greetings,
>
>        apsi
>
> 2017-02-08 17:17 GMT+01:00 ashish dabral <ashis... at gmail.com
> <javascript:>>:
>
>> Hi,
>>
>> I would like to know how to calculate the fermi energy of metals using
>> cp2k.
>> For example, Cu has a fermi energy of around 7.0eV, which can also be
>> calculated using the general formula involving carrier concentration (
>> https://en.wikipedia.org/wiki/Fermi_energy, the
>> three dimensional case.) I would like to know how can I obtain this value
>> (approximate) from the bulk metal unit cell.
>>
>> Thanks
>>
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>
>
>
> --
>
> -=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
>   Ari Paavo Seitsonen / Ari.P... at iki.fi <javascript:> /
> http://www.iki.fi/~apsi/
>     Ecole Normale Supérieure (ENS), Département de Chimie, Paris
>     Mobile (F) : +33 789 37 24 25    (CH) : +41 79 71 90 935
>
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