Author Topic: the obtained transmission are all zero.  (Read 5351 times)

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Offline postnikov

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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?

Offline zh

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Re: the obtained transmission are all zero.
« Reply #1 on: December 7, 2010, 11:44 »
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.

Offline postnikov

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Re: the obtained transmission are all zero.
« Reply #2 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?

Offline postnikov

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Re: the obtained transmission are all zero.
« Reply #3 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.

Offline Anders Blom

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Re: the obtained transmission are all zero.
« Reply #4 on: December 9, 2010, 18:58 »
The convergence pattern is not very stable, so maybe you would need to improve on the numerics a bit, maybe longer electrode. But without seeing the input structure it's impossible to guess. I would generally recommend trying ATK 10.8 which has much improved convergence.

Another reason for the transmission being zero is of course that the system is not conducting... Is T(E) identically zero or just very small?