Re: [Wien] EFG + ETA calculation

2015-02-04 Thread Marcelo Barbosa
I tried to make the supercell as cubic as possible, thus the dimensions 1x3x2.
It is a slightly distorted near-cubic parallelepiped.

I should point that the experiments were done by implanting 111In in the Ga2O3 
samples, which decays to 111Cd.
This means that the position of the probes is given by In, whose ions are 3+ as 
the Ga ones.
However, the electric field gradient is measured after the decay, so it is 
measured in the Cd ions.

Ga2O3 has two Ga sites, octahedral and tetrahedral.
Previous studies in binary oxides using In have shown a preference for In to 
occupy undisturbed cation sites and in cases where an octahedral and a 
tetrahedral sites are present, they have a tendency to go to the octahedral 
site.
In fact, InGaO3 has been reported to have the structure of Ga2O3 with the In 
occupying the octahedral site.
Moreover, the octahedral Ga site in Ga2O3 has a bigger distance to the 
near-neighbors than the tetrahedral site.

With all this information, the most likely scenario is for the In probes to go 
to the octahedral Ga site in Ga2O3 and then they decay to Cd, thus the need to 
simulate the electric field gradient of Cd in the octahedral Ga site.

I haven’t calculated the electronic bands, so I don’t know if there is an 
“impurity” band, but I will look for it.

Isn’t GGA+U or hybrid functionals supposed to change the electric field 
gradient values, or you think the differences are not important in this case?

Once again, thanks for your help,
Marcelo

 On 03/02/2015, at 17:04, Peter Blaha pbl...@theochem.tuwien.ac.at wrote:
 
 The size should be big enough, at least for a first calculation.
 
 Is the supercell nearly cubic, i.e. similar length in all dimensions ?
 
 Is there only one Ga site ?
 
 How are the distances after relaxation ?
 Would it correspond to a more or less axial symmetry or is x,y,z very 
 different and eta=1 is to be expected ??
 
 Cd at an interstitial site ? I'm not sure if a Cd2+ ion really wants to 
 substitute Ga3+.
 Is your cell metallic ?
 Do you find an inpurity band ?
 
 
 Am 03.02.2015 um 11:49 schrieb Marcelo Barbosa:
 Dear Prof Blaha,
 
 The biggest supercell I used for Ga2O3 was 1x3x2, which has 120 atoms.
 Then I changed one of the Ga atoms to Cd and relaxed the atomic positions.
 
 Since GGA+U or hybrids won’t affect the EFG and ETA in this case, do you 
 think I should try bigger supercells?
 
 Thank you very much for your help,
 Marcelo
 
 On 03/02/2015, at 06:43, Peter Blaha pbl...@theochem.tuwien.ac.at wrote:
 
 No, I don't think that for this system GGA+U or hybrids are appropriate.
 
 Is your supercell large enough (~100 atoms) ??
 Did you relax the atomic positions ??
 Maybe the Cd sits in a different position ??
 
 Am 02.02.2015 um 20:09 schrieb Marcelo Barbosa:
 Dear all,
 
 I need to calculate the EFG and ETA in a Cd impurity in Ga2O3 but using 
 the usual GGA method gives me an ETA near 1 when experimentally it is 
 known to be between 0.0 and 0.1.
 I would like then to ask what is the best method to get good EFG and ETA 
 values in such a case:
 - use GGA+U for the 3d orbitals of Ga and 4d orbitals of Cd?
 - use onsite-exact-exchange / hybrid functionals for those orbits?
 - use hybrid functionals for all electrons?
 or do you think these different options won’t change the ETA?
 
 Best regards,
 Marcelo Barbosa
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 --
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 Getreidemarkt 9
 A-1060 Vienna
 Austria
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 -- 
 Peter Blaha
 Inst.Materials Chemistry
 TU Vienna
 Getreidemarkt 9
 A-1060 Vienna
 Austria
 +43-1-5880115671
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Re: [Wien] lapw1.error

2015-02-04 Thread Mohammed Abujafar
Dear Prof. Blaha,I copied my struct file to a new directory and I got the same 
error.Attached is my struct file with two layers for STO and 1.5 layer for LAO. 
I have saved the file and I have

set automatically RMT and continue editing
The initialization was Ok.
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Re: [Wien] EFG + ETA calculation

2015-02-04 Thread Peter Blaha
Cd 2+ has a full d shell and thus the contribution of the d-electrons to 
the EFG should be small. (Try an EFG anylysis).


LDA+U can be important for partially filled d-shells (Ti-Ni), but in any 
case, I'd try GGA+U, but for sure also the other position.


PS: Run   x nn   after relaxations and compare positions and distances 
before/after relaxation.
An ideal octahedra should have Vzz and eta=0. Is your Vzz very small ? 
In this case Vyy and Vxx can have any value and eta is arbitrary, i.e. 
even very small changes in the electronic structure/geometry change eta 
from 0 to 1.

Can you relate the 3 axis of the EFG to the nearest neighbors ?



Am 04.02.2015 um 18:40 schrieb Marcelo Barbosa:

I tried to make the supercell as cubic as possible, thus the dimensions 1x3x2.
It is a slightly distorted near-cubic parallelepiped.

I should point that the experiments were done by implanting 111In in the Ga2O3 
samples, which decays to 111Cd.
This means that the position of the probes is given by In, whose ions are 3+ as 
the Ga ones.
However, the electric field gradient is measured after the decay, so it is 
measured in the Cd ions.

Ga2O3 has two Ga sites, octahedral and tetrahedral.
Previous studies in binary oxides using In have shown a preference for In to 
occupy undisturbed cation sites and in cases where an octahedral and a 
tetrahedral sites are present, they have a tendency to go to the octahedral 
site.
In fact, InGaO3 has been reported to have the structure of Ga2O3 with the In 
occupying the octahedral site.
Moreover, the octahedral Ga site in Ga2O3 has a bigger distance to the 
near-neighbors than the tetrahedral site.

With all this information, the most likely scenario is for the In probes to go 
to the octahedral Ga site in Ga2O3 and then they decay to Cd, thus the need to 
simulate the electric field gradient of Cd in the octahedral Ga site.

I haven’t calculated the electronic bands, so I don’t know if there is an 
“impurity” band, but I will look for it.

Isn’t GGA+U or hybrid functionals supposed to change the electric field 
gradient values, or you think the differences are not important in this case?

Once again, thanks for your help,
Marcelo


On 03/02/2015, at 17:04, Peter Blaha pbl...@theochem.tuwien.ac.at wrote:

The size should be big enough, at least for a first calculation.

Is the supercell nearly cubic, i.e. similar length in all dimensions ?

Is there only one Ga site ?

How are the distances after relaxation ?
Would it correspond to a more or less axial symmetry or is x,y,z very different 
and eta=1 is to be expected ??

Cd at an interstitial site ? I'm not sure if a Cd2+ ion really wants to 
substitute Ga3+.
Is your cell metallic ?
Do you find an inpurity band ?


Am 03.02.2015 um 11:49 schrieb Marcelo Barbosa:

Dear Prof Blaha,

The biggest supercell I used for Ga2O3 was 1x3x2, which has 120 atoms.
Then I changed one of the Ga atoms to Cd and relaxed the atomic positions.

Since GGA+U or hybrids won’t affect the EFG and ETA in this case, do you think 
I should try bigger supercells?

Thank you very much for your help,
Marcelo


On 03/02/2015, at 06:43, Peter Blaha pbl...@theochem.tuwien.ac.at wrote:

No, I don't think that for this system GGA+U or hybrids are appropriate.

Is your supercell large enough (~100 atoms) ??
Did you relax the atomic positions ??
Maybe the Cd sits in a different position ??

Am 02.02.2015 um 20:09 schrieb Marcelo Barbosa:

Dear all,

I need to calculate the EFG and ETA in a Cd impurity in Ga2O3 but using the 
usual GGA method gives me an ETA near 1 when experimentally it is known to be 
between 0.0 and 0.1.
I would like then to ask what is the best method to get good EFG and ETA values 
in such a case:
- use GGA+U for the 3d orbitals of Ga and 4d orbitals of Cd?
- use onsite-exact-exchange / hybrid functionals for those orbits?
- use hybrid functionals for all electrons?
or do you think these different options won’t change the ETA?

Best regards,
Marcelo Barbosa
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--
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Inst.Materials Chemistry
TU Vienna
Getreidemarkt 9
A-1060 Vienna
Austria
+43-1-5880115671
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TU Vienna
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A-1060 Vienna
Austria
+43-1-5880115671

Re: [Wien] EFG + ETA calculation

2015-02-04 Thread Peter Blaha

One more thought:

How is the time delay for In--Cd decay and EFG measurement by PAC ???

Is the Cd already at a relaxed position or still in the In-position ?

You could try to make a structural relaxation for the In-impurity, and 
then calculate the EFG at Cd in the In position without relaxation.


Am 04.02.2015 um 18:40 schrieb Marcelo Barbosa:

I tried to make the supercell as cubic as possible, thus the dimensions 1x3x2.
It is a slightly distorted near-cubic parallelepiped.

I should point that the experiments were done by implanting 111In in the Ga2O3 
samples, which decays to 111Cd.
This means that the position of the probes is given by In, whose ions are 3+ as 
the Ga ones.
However, the electric field gradient is measured after the decay, so it is 
measured in the Cd ions.

Ga2O3 has two Ga sites, octahedral and tetrahedral.
Previous studies in binary oxides using In have shown a preference for In to 
occupy undisturbed cation sites and in cases where an octahedral and a 
tetrahedral sites are present, they have a tendency to go to the octahedral 
site.
In fact, InGaO3 has been reported to have the structure of Ga2O3 with the In 
occupying the octahedral site.
Moreover, the octahedral Ga site in Ga2O3 has a bigger distance to the 
near-neighbors than the tetrahedral site.

With all this information, the most likely scenario is for the In probes to go 
to the octahedral Ga site in Ga2O3 and then they decay to Cd, thus the need to 
simulate the electric field gradient of Cd in the octahedral Ga site.

I haven’t calculated the electronic bands, so I don’t know if there is an 
“impurity” band, but I will look for it.

Isn’t GGA+U or hybrid functionals supposed to change the electric field 
gradient values, or you think the differences are not important in this case?

Once again, thanks for your help,
Marcelo


On 03/02/2015, at 17:04, Peter Blaha pbl...@theochem.tuwien.ac.at wrote:

The size should be big enough, at least for a first calculation.

Is the supercell nearly cubic, i.e. similar length in all dimensions ?

Is there only one Ga site ?

How are the distances after relaxation ?
Would it correspond to a more or less axial symmetry or is x,y,z very different 
and eta=1 is to be expected ??

Cd at an interstitial site ? I'm not sure if a Cd2+ ion really wants to 
substitute Ga3+.
Is your cell metallic ?
Do you find an inpurity band ?


Am 03.02.2015 um 11:49 schrieb Marcelo Barbosa:

Dear Prof Blaha,

The biggest supercell I used for Ga2O3 was 1x3x2, which has 120 atoms.
Then I changed one of the Ga atoms to Cd and relaxed the atomic positions.

Since GGA+U or hybrids won’t affect the EFG and ETA in this case, do you think 
I should try bigger supercells?

Thank you very much for your help,
Marcelo


On 03/02/2015, at 06:43, Peter Blaha pbl...@theochem.tuwien.ac.at wrote:

No, I don't think that for this system GGA+U or hybrids are appropriate.

Is your supercell large enough (~100 atoms) ??
Did you relax the atomic positions ??
Maybe the Cd sits in a different position ??

Am 02.02.2015 um 20:09 schrieb Marcelo Barbosa:

Dear all,

I need to calculate the EFG and ETA in a Cd impurity in Ga2O3 but using the 
usual GGA method gives me an ETA near 1 when experimentally it is known to be 
between 0.0 and 0.1.
I would like then to ask what is the best method to get good EFG and ETA values 
in such a case:
- use GGA+U for the 3d orbitals of Ga and 4d orbitals of Cd?
- use onsite-exact-exchange / hybrid functionals for those orbits?
- use hybrid functionals for all electrons?
or do you think these different options won’t change the ETA?

Best regards,
Marcelo Barbosa
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TU Vienna
Getreidemarkt 9
A-1060 Vienna
Austria
+43-1-5880115671
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A-1060 Vienna
Austria
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Re: [Wien] lapw1.error

2015-02-04 Thread Mohammed Abujafar

 Dear Prof. Blaha,I copied my struct file to a new directory and I got the same 
error.Attached is my struct file with two layers of STO and 1.5 layer of LAO. I 
have saved the struct file and I have also

set automatically RMT and continue editing
The initialization was Ok.Thank you very much for your help in advanceWith best 
regardsMohammed
  

 On Tuesday, February 3, 2015 5:27 PM, Mohammed Abujafar 
mabuja...@yahoo.com wrote:
   

 Dear WIEN2k users,Hi,I am trying to do interface calculations.I have built my 
interface without any problem.The initialization was done successfuly.When I 
start running the scf I got the following: LAPW0 END
SELECT - Error

   stop error
--
 start  (Tue Feb  3 17:10:02 CET 2015) with lapw0 (40/99 to go)

cycle 1 (Tue Feb  3 17:10:02 CET 2015)  (40/99 to go)

   lapw0   (17:10:02) 18.526u 0.239s 0:18.99 98.7% 0+0k 15416+12552io 
 3pf+0w
   lapw1 -c(17:10:21) 0.321u 0.018s 0:00.40 82.5%  0+0k 
 3224+2504io 1pf+0w

   stop error
---I
 have checked out the lapw1.error , I found the following:

 'SELECT' - no energy limits found for atom   7  L= 0  
 'SELECT' - E-bottom   -8.58284   E-top -200.0 
===How
 can I solve this error? Your help is so appreciated.With best regardsMohammed





   

STO-LAO-interface-1.struct
Description: Binary data
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Re: [Wien] lapw1.error

2015-02-04 Thread Mohammed Abujafar
 


Correction: attached file contains 2.5 layers of STO instead of 2 layers and 
1.5 layers of LAO
 
 Dear Prof. Blaha,I copied my struct file to a new directory and I got the same 
error.Attached is my struct file with two layers of STO and 1.5 layer of LAO. I 
have saved the struct file and I have also

set automatically RMT and continue editing
The initialization was Ok.Thank you very much for your help in advanceWith best 
regardsMohammed
  

 On Tuesday, February 3, 2015 5:27 PM, Mohammed Abujafar 
mabuja...@yahoo.com wrote:
   

 Dear WIEN2k users,Hi,I am trying to do interface calculations.I have built my 
interface without any problem.The initialization was done successfuly.When I 
start running the scf I got the following: LAPW0 END
SELECT - Error

   stop error
--
 start  (Tue Feb  3 17:10:02 CET 2015) with lapw0 (40/99 to go)

cycle 1 (Tue Feb  3 17:10:02 CET 2015)  (40/99 to go)

   lapw0   (17:10:02) 18.526u 0.239s 0:18.99 98.7% 0+0k 15416+12552io 
 3pf+0w
   lapw1 -c(17:10:21) 0.321u 0.018s 0:00.40 82.5%  0+0k 
 3224+2504io 1pf+0w

   stop error
---I
 have checked out the lapw1.error , I found the following:

 'SELECT' - no energy limits found for atom   7  L= 0  
 'SELECT' - E-bottom   -8.58284   E-top -200.0 
===How
 can I solve this error? Your help is so appreciated.With best regardsMohammed







   

STO-LAO-interface-1.struct
Description: Binary data
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Re: [Wien] lapw1.error

2015-02-04 Thread Peter Blaha
I'm abroad and cannot display your struct file correctly, nor can I test 
it at the moment.


However, I saw that all RMT=2.0 which is for sure not correct.

Am 04.02.2015 um 19:26 schrieb Mohammed Abujafar:




Correction: attached file contains 2.5 layers of STO instead of 2 layers
and 1.5 layers of LAO

Dear Prof. Blaha,
I copied my struct file to a new directory and I got the same
error.Attached is my struct file with two layers of STO and 1.5 layer of
LAO. I have saved the struct file and I have also


  set automatically RMT and continue editing
  http://astroem.phys.uniroma1.it:7890/util/structrmt.pl?SID=521174

The initialization was Ok.Thank you very much for your help in advance
With best regards
Mohammed


On Tuesday, February 3, 2015 5:27 PM, Mohammed Abujafar
mabuja...@yahoo.com wrote:


Dear WIEN2k users,
Hi,
I am trying to do interface calculations.I have built my interface
without any problem.The initialization was done successfuly.When I start
running the scf I got the following:

  LAPW0 END
SELECT - Error


  stop error

--

  start (Tue Feb  3 17:10:02 CET 2015) with lapw0 (40/99 to go)

 cycle 1(Tue Feb  3 17:10:02 CET 2015)  (40/99 to go)


  lapw0 (17:10:02) 18.526u 0.239s 0:18.99 98.7% 0+0k 15416+12552io 
3pf+0w
  lapw1 -c  (17:10:21) 0.321u 0.018s 0:00.40 82.5%  0+0k 3224+2504io 1pf+0w



  stop error


---
I have checked out the lapw1.error , I found the following:

  'SELECT' - no energy limits found for atom   7  L= 0
  'SELECT' - E-bottom   -8.58284   E-top -200.0
===
How can I solve this error? Your help is so appreciated.
With best regards
Mohammed









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Inst.Materials Chemistry
TU Vienna
Getreidemarkt 9
A-1060 Vienna
Austria
+43-1-5880115671
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