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General Questions and Answers / Re: Spin transmission spectrum messed up
« on: October 6, 2016, 05:24 »
Thank you, I will try, But I don't think it is the problem of tolerance
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General Questions and Answers / Spin transmission spectrum messed up
« on: October 5, 2016, 16:03 »
Hi,
I got a fake spin transmission spectrum,
half of the spin up spectrum is regraded as spin down spectrum by the software,
and half of the spin down spectrum is regarded as spin up spectrum.
The data messed up!
compare the two figures below, they are obtained by changing the iteration tolerance from 0.005 to 0.002.
I got a fake spin transmission spectrum,
half of the spin up spectrum is regraded as spin down spectrum by the software,
and half of the spin down spectrum is regarded as spin up spectrum.
The data messed up!
compare the two figures below, they are obtained by changing the iteration tolerance from 0.005 to 0.002.
3
General Questions and Answers / Re: The calculation did not converge when the scattering region is long
« on: July 27, 2016, 14:42 »
OK, I will try it.
Thank you!
Thank you!
4
General Questions and Answers / Re: The calculation did not converge when the scattering region is long
« on: July 26, 2016, 05:07 »
Here are two of the scripts that can't converge. The output files are too large to upload.
By the way, is it useful to tune the "Damping factor" or the "History steps" to get faster convergence?
Please give me more advices.
Thank you very much!
By the way, is it useful to tune the "Damping factor" or the "History steps" to get faster convergence?
Please give me more advices.
Thank you very much!
5
General Questions and Answers / The calculation did not converge when the scattering region is long
« on: July 24, 2016, 09:49 »
Hi,
I optimized a unit cell of graphene nanoribbon, and then repeat it to different lengths to calculate IV curves with the DFTB method.
However, I found that when the scattering region is long, 15 unit cells for example, the calculation is unable to converge to the requested tolerance (e-05) even when the maximum steps is set to be 1000.
But the problem is absent when the scattering region is short, 7 unit cells for example.
Is this normal?
Does that mean we can only study short structures with the software?
Thank you
I optimized a unit cell of graphene nanoribbon, and then repeat it to different lengths to calculate IV curves with the DFTB method.
However, I found that when the scattering region is long, 15 unit cells for example, the calculation is unable to converge to the requested tolerance (e-05) even when the maximum steps is set to be 1000.
But the problem is absent when the scattering region is short, 7 unit cells for example.
Is this normal?
Does that mean we can only study short structures with the software?
Thank you
6
General Questions and Answers / Re: VibrationalMode
« on: July 20, 2016, 07:12 »
Just as you said, the problem is solved.
Thank you very much!
Thank you very much!
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General Questions and Answers / Re: VibrationalMode
« on: July 17, 2016, 08:43 »
Hi,
Actually, I want to get the coordinates of the vibrating model, like a car file or a cif file, instead of a picture.
I have tried your method.
I first read the nc file: a=nlread('myncfile.nc')[4]
And then tried to obtain the information of a mode with the command "a. mode(1, 300*Kelvin)"
but something goes wrong (The mode ... is not available).
Can you give me some further advices?
Thank you!
Actually, I want to get the coordinates of the vibrating model, like a car file or a cif file, instead of a picture.
I have tried your method.
I first read the nc file: a=nlread('myncfile.nc')[4]
And then tried to obtain the information of a mode with the command "a. mode(1, 300*Kelvin)"
but something goes wrong (The mode ... is not available).
Can you give me some further advices?
Thank you!
8
General Questions and Answers / VibrationalMode
« on: July 2, 2016, 17:04 »
When I look at the vibration of a structure through the VibrationalMode, I want to obtain the coordinates of the structure at a certain time point,
How can I make it? The Vibration Visualizer provide only the option to export images!
How can I make it? The Vibration Visualizer provide only the option to export images!
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General Questions and Answers / Re: Can DFTB in ATK_2015 calculate Spin polarized Bandstructure?
« on: June 17, 2016, 10:30 »
OK!
10
General Questions and Answers / Re: Calculating the spin polarization of a Zigzag GNR with DFTB
« on: June 17, 2016, 09:22 »
The py file is much more complex than I expected, and I don't know how to generate it with the VNL.
Although the degeneration of the band is eliminated, the bandstructure is still quite different with the one calculated by DFT.
However, I just found that the DFTB works well on ZGNRs that passived by hydrogen,
I wonder wheter passivation is necessary for considering Spin with DFTB?
Although the degeneration of the band is eliminated, the bandstructure is still quite different with the one calculated by DFT.
However, I just found that the DFTB works well on ZGNRs that passived by hydrogen,
I wonder wheter passivation is necessary for considering Spin with DFTB?
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General Questions and Answers / Re: Can DFTB in ATK_2015 calculate Spin polarized Bandstructure?
« on: June 17, 2016, 08:50 »
Hi Jess,
According to references and the DFT calculation, a band gap is expected to appear when the ZGNR is antiferromagnetic.
According to references and the DFT calculation, a band gap is expected to appear when the ZGNR is antiferromagnetic.
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General Questions and Answers / Can DFTB in ATK_2015 calculate Spin polarized Bandstructure?
« on: June 17, 2016, 06:44 »
The simulation result is not right.
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General Questions and Answers / Re: Calculating the spin polarization of a Zigzag GNR with DFTB
« on: June 17, 2016, 03:55 »
Hi Zh,
Thank you for your reply.
I did set only the edge carbon atoms magnetic, but I'm not sure whether they converged as expected.
Below is the py file, please take a look at it.
Thanks again!
Thank you for your reply.
I did set only the edge carbon atoms magnetic, but I'm not sure whether they converged as expected.
Below is the py file, please take a look at it.
Thanks again!
14
General Questions and Answers / Calculating the spin polarization of a Zigzag GNR with DFTB
« on: June 16, 2016, 18:02 »
Hi,
I have tried to calculate the bandstructure of a ZGNR with the DFTB, the spin is set to be polarized,
but the calculated banstructure turns to be degenerate no matter the ZGNR is ferromagnetic or antiferromagnetic,
Why?
I have tried to calculate the bandstructure of a ZGNR with the DFTB, the spin is set to be polarized,
but the calculated banstructure turns to be degenerate no matter the ZGNR is ferromagnetic or antiferromagnetic,
Why?
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