Dear developers,
I am trying to understand how the variation of occupations and Fermi level
is implemented in density-functional perturbation theory for metals. In the
Baroni, de Gironcoli, and Dal Corso Rev Mod Phys paper on DFPT, this issue
appears in equations 68 and 75-79. I see that routine e
Hello,
I am still wondering about this question and haven't gotten any response.
Can anyone help clarify the relation between the equations in the Rev Mod
Phys paper and the code?
Thanks,
David Strubbe
UC Berkeley
On Fri, Apr 8, 2011 at 11:39 AM, David Strubbe wrote:
> Dear developers,
>
> I am
On Apr 8, 2011, at 20:39 , David Strubbe wrote:
> Eq. 79 refers to a quantity \Delta n_{ext} and an integral of the LDOS
> with \Delta V_{SCF} to calculate the shift in Fermi level. However in
> ef_shift it appears that the density response drhoscf is used instead
> of these quantities in the num
Paolo,
Thanks for the response. This gives me some more insight into what is going
on, but I still don't understand.
As far as I can tell, the drhoscf in ef_shift is still the change in the
density rather than the change in the potential, because the calls in
solve_linter to dv_of_drho are using
Dear David Strubbe,
eq. 79 is a general formula; in the phonon code Delta n_ext(q=0) is
always vanishing because the perturbation is neutral (atoms are
displaced but their charge is not changed), still Delta Vscf is in
general non zero so one has to do something
Let's look at the scf variation
Stefano,
Thank you for the explanation. Things are clear now. Is there a circumstance
in which Delta n_ext(q=0) is nonzero?
David Strubbe
UC Berkeley
On Wed, Apr 20, 2011 at 1:12 AM, Stefano de Gironcoli wrote:
> Dear David Strubbe,
>
> eq. 79 is a general formula; in the phonon code Delta n_e
It might happen if you transform one atom into another like in the
"computational alchemy" approach [PRL 66 2116( 1991)]
stefano
On 04/20/2011 09:51 PM, David Strubbe wrote:
> Stefano,
>
> Thank you for the explanation. Things are clear now. Is there a circumstance
> in which Delta n_ext(q=0) is
