Author Topic: Is this result credible  (Read 1638 times)

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Offline FlyFlower

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Is this result credible
« on: November 9, 2012, 08:20 »
hello, everyone, when i perform a two-probe calculation by using ATK-2008.10, at a bias of 1.0V, the self-consistent iteration is as follows:

# sc 117 : q =  668.98978 e  dRho =  3.4729E+00
# sc 118 : q =  669.07139 e  dRho =  1.5897E+00
# sc 119 : q =  669.13534 e  dRho =  3.4033E+00
# sc 120 : q =  669.13711 e  dRho =  7.8281E-03
# sc 121 : q =  669.14372 e  Etot = -7024.61255 Ry  dRho =  1.2260E-01
# sc 122 : q =  669.14696 e  Etot = -7024.61370 Ry  dRho =  8.1020E-01  dEtot = -1.1522E-03 Ry
# sc 123 : q =  669.15218 e  Etot = -7024.59930 Ry  dRho =  4.0362E-01  dEtot =  1.4403E-02 Ry
# sc 124 : q =  669.14950 e  Etot = -7024.59930 Ry  dRho =  2.9539E-01  dEtot = -3.6075E-06 Ry
1.0      8.41e-08

this current has a 2~3 orders of magnitude difference from those of bias on both sides,

voltage(V)     current(A)
0.8      1.03E-5
1.0      8.41E-8
1.2      6.73E-6

is this result credible? thanks very much!

Offline kstokbro

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Re: Is this result credible
« Reply #1 on: November 9, 2012, 10:06 »
It is difficult to tell from your information and ATK-2008.10 is no longer supported so we can not test it further.
I recommend that you perform the calculation we our latest version and compare the results,


Offline Anders Blom

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Re: Is this result credible
« Reply #2 on: November 9, 2012, 10:59 »
From just looking at the output it seems this calculation has not converged nicely. It does hit a point with small dEtot, but dRho is large, so it's more a coincidence that dEtot happens to be small perhaps. Also if you need over 100 iterations and still have dRho so large after 120 iterations, it should be possible to improve the convergence. But, as was mentioned above, this version is so old that we cannot support it even if we wanted to.