[Pw_forum] simulated STM image

[Madhura Marathe]

 Dear all,

 I have been trying to find the simulated STM images for some surfaces. I
have some doubts about the procedure:

1) The option of 'stm_wfc_matching' is not working. According to some
forum posts, it has been disabled for some latest versions. The working of
that option itself was not very clear to me from documentation, but why
was that disabled?
 And if necessary, can I use the wave-functions and charge density files
from the latest version for the older version post-processing tools, to
get this option working?

2) I am interested to know that because from calculations what we get is
ILDOS and we plot it some fixed plane. This will correspond to
"constant-height" mode of the STM experiments. However, more common mode
in experiments is "constant-current"; and that wave-function matching
option has some z and dz parameters which probably were used to get the
image corresponding to the latter mode. Is that correct guess?

3) I have seen some papers which give simulated STM images calculated at
"constant-current" mode using QE (e.g. - Valentin, JCP 2007). So does
there exist some post-processing tool to calculate that? If yes, where can
I find it?

 Thanks and regards,
 Madhura.

-- 
Madhura Marathe,
PhD student, TSU,
JNCASR, Bangalore.
India.
Phone No: +91-80-22082835

[Pw_forum] question about constrained magnetization

[Gabriele Sclauzero]

Cyrille Barreteau wrote:
> Dear Gabriele
> 
> The last solution that you provided seems to be the most adapted to my 
> problem.
> The choice of the initial moment is maybe not the most adapted but this 

I think there is a possibility to fix this as well, but I don't know if this 
solution may 
have any bad side effects.
You should move the check on starting magnetization after reading the 
pseudopotential, 
i.e. right after

   CALL readpp ()

AND convert from "starting magnetization" to "starting spin polarization" 
before checking:

   !
   ! ... read pseudopotentials
   !
   CALL readpp()
   !
   DO nt = 1, ntyp
  !
  IF ( starting_magnetization(nt) == sm_not_set ) THEN
 starting_magnetization(nt) = 0.0_dp
  ELSE
 starting_magnetization(nt) = starting_magnetization(nt)/zv(nt)
 IF ( starting_magnetization(nt) > 1.0_dp ) THEN
starting_magnetization(nt) = 1.0_dp
 ELSE IF ( starting_magnetization(nt) <-1.0_dp ) THEN
starting_magnetization(nt) =-1.0_dp
 END IF
  END IF
  !
   END DO
   starting_magnetization_ = starting_magnetization

You will also need to include zv from the ions_base module, by substituting

   USE ions_base, ONLY : if_pos, ityp, tau, extfor, &

with:

   USE ions_base, ONLY : if_pos, ityp, tau, extfor, zv,&

at the beginning of the subroutine iosys.


Regards,

Gabriele



> not a
> very big problem.. thanks for this very quick fix:-)
> 
> cyrille
> 

-- 


o  o
| Gabriele Sclauzero, PhD Student  |
| c/o:   SISSA & CNR-INFM Democritos,  |
|via Beirut 2-4, 34014 Trieste (Italy) |
| email: sclauzer at sissa.it |
| phone: +39 040 3787 511  |
| skype: gurlonotturno |
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