Messages

1

General Questions and Answers / Re: The maximum voltage could be applied between two metal electrodes?

« on: September 16, 2012, 13:58 »

Do you mean source/drain voltage, or gate voltage? Anyway, in principle none of them are limited, and ATK also contains special algorithms for handling large bias, so it should usually be possible to reach 5 V source drain bias, although convergence is always a bit tougher at high bias. For the gate voltages you can apply very high numbers, since it's the field, rather than the voltage itself, which matter.

Thanks!

I mean the source-drain voltage.
As for atk 2008.10, the source-drain  bias could reach 5V?

2

General Questions and Answers / The maximum voltage could be applied between two metal electrodes?

« on: September 16, 2012, 05:25 »

In the current calculation mechanism, could someone tell me
the maximum voltage which could be applied between two metallic electrodes?
 3V 4V or 5V?

3

General Questions and Answers / Re: The error about repeating previous PRL result.

« on: September 22, 2011, 04:21 »

please find attached a gga semicore pseudopotentials for Vanadium
it is from M. Krack, see Theor. Chem. Acc. 114, 145 (2005) and converted to the upf format. There is also an example of how to setup the basis set.

The inclusion of semicore  states gives a large difference for the gga calculations for the present system. As you can see in the attached
the momen on V is 1.25, and the total moment of the molecule is  0.99.

We plan to include all the pseudo potentials from the above paper in the final release of ATK11.8, i.e. an additional set of  semi-core and only valence pseudo potentials for LDA and GGA.

kstokbro, thank you for your work very much.
However, in our group the used atk version is 2008.10, so could you provide me the corresponding basis for the atk 2008.10?
Thank again!

4

General Questions and Answers / Re: The error about repeating previous PRL result.

« on: September 22, 2011, 04:01 »

please find attached a gga semicore pseudopotentials for Vanadium
it is from M. Krack, see Theor. Chem. Acc. 114, 145 (2005) and converted to the upf format. There is also an example of how to setup the basis set.

The inclusion of semicore  states gives a large difference for the gga calculations for the present system. As you can see in the attached
the momen on V is 1.25, and the total moment of the molecule is  0.99.

We plan to include all the pseudo potentials from the above paper in the final release of ATK11.8, i.e. an additional set of  semi-core and only valence pseudo potentials for LDA and GGA.

Thank all of you for your hard work!

5

General Questions and Answers / Re: The error about repeating previous PRL result.

« on: September 18, 2011, 03:37 »

We are working on trying to find a pseudopotential and basis for you, but it might be a little delayed since we are also busy finalizing the release.

No problem!

Thank all of you for your work!

6

General Questions and Answers / Re: The error about repeating previous PRL result.

« on: September 15, 2011, 19:46 »

Ok (was hard to tell if it was just small or zero). But the band edge is very close to Ef, closer than in the PRL I think, so I guess the V core/basis set matters a lot.

How about the PP and basis?

7

General Questions and Answers / Re: The error about repeating previous PRL result.

« on: September 14, 2011, 17:54 »

In the pp we have in ATK right now, 3p is pure core. You can try the SIESTA pp in ATK, as long as it's a UPF file with the right format and no off-diagonal projectors. You do however have to make a customized basis set then to include 3p. Not too hard, the pp is the tricky bit.

My DOS is similar, just shifted a bit. Is your majority DOS @ Ef zero or finite?

The majority DOS @ Ef is zero, as shown in the above fig.

Could you provide the modified V pp and basis including 3p for me and other ATK users.

As you know, the Up-Down is about 0.6 or 0.7, it is very different from the result published in Phys. Rev. Lett. and the SIESTA code.

So if the modified V pp and basis are provided, the other people can also adopt them in their research work about V.

8

General Questions and Answers / Re: The error about repeating previous PRL result.

« on: September 14, 2011, 17:37 »

My Mulliken populations show Q(up)-Q(down) about 0.7, I'm just trying to wrap my head around if there is a factor of 2 for the Bohr magneton, as that would put it around 1.4 as in the article...?

Input attached; I also tried the hexagonal configuration they use in the article, but it makes no difference.

This is my siesta calculation result.

Q(up)-Q(down) =0.9993

In my SIESTA calculation, V 3p is considered as the semicore state in the used PP and basis.

How about the ATK code?

9

General Questions and Answers / Re: The error about repeating previous PRL result.

« on: September 14, 2011, 16:26 »

I can confirm ATK predicts a metallic ferromagnetic state. The DOS resembles that in the article (you need 200 kz-points or so) but the majority states are slightly shifted so there is finite DOS at the Fermi level.

This might be a basis set effect, the article uses a rather different basis set. Maybe with LDA+U things would change a bit in ATK? They try this in the article without seeing a major effect, but perhaps ATK needs it to shift the bands slightly? You can try this!

How about the  magnetic moment?
Can you show your input file ?

10

General Questions and Answers / Re: The error about repeating previous PRL result.

« on: September 14, 2011, 10:45 »

1). You had better use a same exchange correlation functional with the one used in literature.
2). In the setup of initial spins of atoms, only the vanadium atom is required.

I have change the XC function into GGA, and the inital spin is set only for V, the

result is very similar to the previous calculation, ie, M is also 0.6 ub

 ATK developers could like to check this case for me?

11

General Questions and Answers / The error about repeating previous PRL result.

« on: September 13, 2011, 08:39 »

The error about repeating previous PRL result.

These days, I repeat the calculation results of PRL 97,09201(2006).
My obtained magnetic moment per unit cell in the one-dimensional vanadium-benzene wire system is
about 0.55ub,however, the above PRL paper show the magnetic moment should be 1 ub unit cell.

Is it my own input file error,or the atk code itself?

Could someone give me some advice?

The input file is attached!

12

General Questions and Answers / Re: the obtained transmission are all zero.

« on: December 9, 2010, 12:56 »

Anders Blom， could you give me some advice about such a problem?

I notice someone have the same problem, however, no method is given.

13

General Questions and Answers / Re: the obtained transmission are all zero.

« on: December 7, 2010, 12:10 »

First, you had better check the log file of your job. Particularly, see whether the total charge is converged to zero or not. If the total charge is converged to nearly zero, the 3rd and 4th parameters mentioned by you need to be tuned.

You are right. I first check my structure, then read my log file to check the charge. However, everything is OK, shown  as follow.

# sc 45 : q =  277.45785 e  Etot = -1292.40783 Ry  dRho =  1.1254E-02  dEtot = -4.0064E-03 Ry
# sc 46 : q =  277.43865 e  Etot = -1292.40513 Ry  dRho =  7.4815E-03  dEtot =  2.6987E-03 Ry
# sc 47 : q =  277.43211 e  Etot = -1292.40419 Ry  dRho =  3.2435E-03  dEtot =  9.4009E-04 Ry
# sc 48 : q =  277.41565 e  Etot = -1292.40180 Ry  dRho =  6.6191E-03  dEtot =  2.3908E-03 Ry
# sc 49 : q =  277.45588 e  Etot = -1292.40747 Ry  dRho =  1.5931E-02  dEtot = -5.6712E-03 Ry
# sc 50 : q =  277.25674 e  Etot = -1292.37649 Ry  dRho =  8.4306E-02  dEtot =  3.0977E-02 Ry
# sc 51 : q =  277.35372 e  Etot = -1292.39248 Ry  dRho =  4.2263E-02  dEtot = -1.5981E-02 Ry
# sc 52 : q =  277.40286 e  Etot = -1292.39985 Ry  dRho =  2.0517E-02  dEtot = -7.3707E-03 Ry
# sc 53 : q =  277.43945 e  Etot = -1292.40509 Ry  dRho =  1.4680E-02  dEtot = -5.2436E-03 Ry
# sc 54 : q =  277.35574 e  Etot = -1292.39272 Ry  dRho =  3.4311E-02  dEtot =  1.2374E-02 Ry
# sc 55 : q =  277.35565 e  Etot = -1292.39271 Ry  dRho =  6.3075E-05  dEtot =  7.3768E-06 Ry


Zh, thanks, any other suggestion?

14

General Questions and Answers / the obtained transmission are all zero.

« on: December 7, 2010, 02:53 »

In my current calcultion, the obtained  transmission  are all zero.
I have try to change:

1) all kinds of bases, DZP,SZP etc.
2) Mesh-cutoff,
3) integral_lower_bound and circle_points
4) green_function_infinitesimal

How can I get the right transmission?

15

General Questions and Answers / Re: So difficult in converence

« on: July 11, 2010, 08:40 »

1500 Kelvin in electronic temperature?

So high temperature?

the results are also accurate?