On Thu, 19 Apr 2007, Yurko Natanzon wrote:
| Dear Adam Gali, Andrei Postnikov,
| thank you for explanation. Actually, I'm not interested in particular
| numbers, but want to observe changes in ionic charges of atoms,
| neighboring to dopant and the dependence of such changes on a dopant
| concentr
ok, there some papers which use Mulliken population with SIESTA. For
example, this one:
http://arxiv.org/pdf/cond-mat/0008340
The authors say that differences (of net charges and BOP-s) are less
sensitive to the choice of basis sets, so they can be meaningful. Can
anybody confirm this?
On 19/04/0
Dear Adam Gali, Andrei Postnikov,
thank you for explanation. Actually, I'm not interested in particular
numbers, but want to observe changes in ionic charges of atoms,
neighboring to dopant and the dependence of such changes on a dopant
concentration (comparabale to undoped system). Is it possible
Dear Yurko Natanzon,
take care! Mulliken-charges could be meaningless by using diffusing
orbitals. Draw the net charge density around the atoms (you can do it by
SIESTA and utility programs provided with) and you can see that O is
negatively polarized while Si is positively polarized opposit
On Thu, 19 Apr 2007, Yurko Natanzon wrote:
| Well, this works for TiO2, but when I tried to do it with SiO2, I've got:
|
| then oxygen has positive ionic charge (6-5.987), and silicon has
| negative (4-4.026). Does it make any sense??
Dear Yurko:
they have no more sense than "ionic charge" in ge
Well, this works for TiO2, but when I tried to do it with SiO2, I've got:
mulliken: Atomic and Orbital Populations:
Species: Si
Atom Qatom Qorb
3s 3s 3py 3pz 3px 3py 3pz 3px
3Pdxy 3Pdyz 3Pdz2 3Pdxz 3Pdx2-y2
1 4.026 0.404 0
Just subtract the ionic charge from the Mulliken population, you will get
-.514 for O and +1.028 for Ti.
2007/4/19, Yurko Natanzon <[EMAIL PROTECTED]>:
Dear SIESTers,
I wonder how to calculate net ionic charge with SIESTA. For example, I
have TiO2 anatase supercell with 12 atoms. Pseudopotentia
Dear SIESTers,
I wonder how to calculate net ionic charge with SIESTA. For example, I
have TiO2 anatase supercell with 12 atoms. Pseudopotential for Ti has
valence electrons in 3s2 3p6 3d2 4s2 (12 electrons), O has 2s2 2p4 (6
electrons). Then i set WriteMullikenPop 2 and obtain
10.972 for each Ti
Hello everybody.
In the previous mail John Baba said that we can't use NetCharge -1 in
bulk. Can anyone explain why?
When you add the compensating background you introduce some spurious
term in the total energy [Makov and Payne, PRB 51, 4014 (1995)] which
can be corrected somehow a posterior
Hi all,
I forgot to mention that there is really a problem of infinite array of
charged supercells if NetCharge is set to +1 or -1 when periodic
boundary conditions are used. But there are terms which can overcome
this problems if for example formation energies are calculated.
Bozidar
Hi everyone,
I think connected to this problem is evaluation of donor or acceptor
levels in doped materials. So if you want to find donor level you should
use something like:
X(0/+) = R(0/+) + [E(X0) − E(X+)] − [E(R0) − E(R+)]
where R(0/+) is donor level of reference state (this is known
e
Hi, Artyukhov,
Do you mean that we need not set extra options in fdf file? But what´s
the difference to the neutral states? can you give more detail instruction
about AUTOMATIC? Thank u very much!!
K.P.Wang
2007/4/19, Vasilii Artyukhov <[EMAIL PROTECTED]>:
I guess this is more or less auto
I guess this is more or less automatic.
2007/4/19, Wang kunpeng <[EMAIL PROTECTED]>:
Hi, all
Here I find a literature Phys.Rev.B 70, 165110 (2004) which described
charge doping with siesta. Additional charge was added by the injection of
extra electrons in the system, with charge neutrality ove
Hi, all
Here I find a literature Phys.Rev.B 70, 165110 (2004) which described charge
doping with siesta. Additional charge was added by the injection of extra
electrons in the system, with charge neutrality over space bing ensured by a
corresponding homogeneous positively charged background. But I
Thank u very much! John.
Yes, impurity doping is one way, but generally it needs a large supercell.
So we can
add the desired concentration of holes or electrons to the bulk system
instead of the impurity doping. As u mentioned that P doping in bulk Si, we
can also add the desired concentration o
Hi wang:
You can not set the option: NerCharge=-1 in bulk. In other words,
you must not introduce NerCharge in bulk system! You can find this
in the manual of SIESTA.
If you want to in troduce hole or electron, I know one way, you
can choose a dopeing impurity. Just as P and N for bulk Si.
Hi, All:
how to dope a hole or electron in a bulk crystal? I set the option:
NetCharge=-1: as the castep do, that I supposed to dope a electron in a
peoridic system. But the DOS I calculated is very different to the
literature. Can u tell me what´s the problem? Thank u very much!!
Yours
K.P.Wa
Dear all,
I'd like to do some geometry optimization calculation about tetragonal bulk
PbTiO3. The restricted realaxtion using constr.f works very well. Thanks
Pablo Aguado and Gali Ádám. But I found that the convergence of the CG
algorithm is very slow as well as broyden algorithm, even after 47
What you see is partial filling of bands, try using only one k-point and you
will see that your spin is integral.
2007/4/19, Rainer Hoft <[EMAIL PROTECTED]>:
Dear Siesta users,
I have a question with regards to "spin contamination", yet I'm not
sure if this is the correct terminology to use in
Dear Siesta users,
I have a question with regards to "spin contamination", yet I'm not
sure if this is the correct terminology to use in my context.
SIESTA gives as part of its output the "spin polarisation", SP= Q_up -
Q_down. So for a singlet this is 0, for a doublet 1, a triplet 2 etc.
But
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