[Wien] Is it possible artificially shift Fermi level for optical calculations?

[Peter Blaha]

a) Is it necessary that you create a supercell with such a dipole ?
    Can't you put the graphene on both sides and make a symmetric slab ?

b) The easiest way is probably to rerun   x lapw2 -fermi with different 
NE in case.in2. Vary NE until EF is where you want it. However, I don't 
think it helps you much with optic. When you change EF in this way, your 
"semiconductor" is a metal and you will include such transitions in the 
optic calculations.

If suggestion a) is not possible ?? one could eventually add an electric 
field, but all these things are uncontrolled approximations. If graphene 
is affected by the semiconductor, you need a simulation cell which is 
large enough to do it right.

On 11/11/2014 02:46 PM, Martin Gmitra wrote:
> My system is a metal, and should be a semimetal (it is graphene on a
> semiconduncting surface). Wien2k gives hole doping of graphene. Once a
> dipole correction would be included (cross-checked in Quantum
> Espresso), the Fermi level should lie at the Dirac point. From there
> came my question about shifting of the Fermi level. The Fermi level in
> fact determines which transitions from occupied to unoccupied states
> take place.
>
> Best regards,
> Martin Gmitra
>
> On Tue, Nov 11, 2014 at 9:48 AM, Peter Blaha
> <pblaha at theochem.tuwien.ac.at> wrote:
>> I'm not sure I understand. How should EF affect your calculation of optics ?
>>
>> Is this a metal or an insulator ?
>>
>> If you want a bigger gap you can use a "scissors"-shift in case.inkram.
>>
>>
>>
>> On 11/10/2014 06:28 PM, Martin Gmitra wrote:
>>>
>>> Dear Wien2k users,
>>>
>>> I am dealing with a slab system having a significant dipole moment.
>>> Therefore, there is a Fermi level offset. I would like to calculate
>>> optical properties of the system while I need to artificially shift
>>> Fermi level. Do you have an idea how to do that?
>>>
>>> Best regards,
>>> Martin Gmitra, Uni Regensburg
>>> _______________________________________________
>>> Wien mailing list
>>> Wien at zeus.theochem.tuwien.ac.at
>>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>>> SEARCH the MAILING-LIST at:
>>> http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
>>>
>>
>> --
>>
>>                                        P.Blaha
>> --------------------------------------------------------------------------
>> Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
>> Phone: +43-1-58801-165300             FAX: +43-1-58801-165982
>> Email: blaha at theochem.tuwien.ac.at    WIEN2k: http://www.wien2k.at
>> WWW:   http://www.imc.tuwien.ac.at/staff/tc_group_e.php
>> --------------------------------------------------------------------------
>> _______________________________________________
>> Wien mailing list
>> Wien at zeus.theochem.tuwien.ac.at
>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>> SEARCH the MAILING-LIST at:
>> http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
> _______________________________________________
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
> SEARCH the MAILING-LIST at:  http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
>

-- 

                                       P.Blaha
--------------------------------------------------------------------------
Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-165300             FAX: +43-1-58801-165982
Email: blaha at theochem.tuwien.ac.at    WIEN2k: http://www.wien2k.at
WWW:   http://www.imc.tuwien.ac.at/staff/tc_group_e.php
--------------------------------------------------------------------------