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91
General Questions and Answers / Re: Bias direction for different electrodes
« Last post by lohy on October 2, 2024, 10:27 »
Okay thanks.

Let's say I am looking at the transmission via the IVCharacteristics. The current there is (just to give a number) 1.4*10**-5 at 1V.

To get this current (1.4*10**-5)  at 1V the code would then have the bias window in the transmission spectrum from -0.5 to 0.5 - is the correct?  Or, would the code have the bias window from 0 to  -1V?

I ask about this because I am using the transmissionspectrum to investigate what happens when do an IV sweep - but to do so I need to be sure how the current is integrated from the transmission spectrum.
92
General Questions and Answers / Re: Grain Boundary Scattering doping problem
« Last post by Anders Blom on October 2, 2024, 01:22 »
As suspected, the tags are not transferred, and modifying the code to allow this would be very hard. So, you are basically left with the option to put together the workflow yourself. It's actually not that complicated, the study object primarily makes it easy to do for a large amount of different grain boundaries, but the steps it performs for each one are described in the manual:
https://docs.quantumatk.com/manual/Types/GrainBoundaryScattering/GrainBoundaryScattering.html#grainboundaryscattering

Note also that you need to passivate the dangling bonds in the grain boundary with hydrogen, else you will have very strong scattering from these. This is also something the automatic flow is not designed to do.
93
General Questions and Answers / Re: Grain Boundary Scattering doping problem
« Last post by Anders Blom on October 1, 2024, 01:18 »
I made some modifications to the script, most notably I switched the DFT calculator to a Slater-Koster tight-binding and used a Tersoff potential to relax it. That way I can do a full run in less than a minute on my laptop, so this is a lot easier to use for troubleshooting. The basic principles are exactly the same as in DFT though.

Now, I also get r=1 in this case, but again for obvious reasons: the entire transmission is basically zero.

I have a suspicion that this is quite simply because the doping tag is not promoted internally when the configurations are generated. The whole workflow was done for metals so this particular use case was not considered, although propagating tags would in general be a good idea, for other purposes too. Let me check with our developers.
94
General Questions and Answers / Re: Bias direction for different electrodes
« Last post by Anders Blom on September 30, 2024, 20:27 »
Yeah maybe this is the key. In the IVCharacteristics version for computing the transmission, the "source" electrode is set to zero, and the bias applied to the "drain". And with the keyword that we discussed source_electrode you pick which is left/right. Does that help?

Still note that this is all "relative and arbitrary" in the sense that you can always shift an energy scale around, since it has no fixed absolute zero. It is true that for basic TransmissionSpectrum the bias is applied symmetrically, although this is only so because you set a "bias" in the GUI; if you look at the script it will still set the individual electrode voltages, and this can be shifted arbitrarily with no effect on the results as long as the difference remains the same (the bias).
95
General Questions and Answers / Re: Bias direction for different electrodes
« Last post by lohy on September 30, 2024, 14:53 »
It actually might just be that it is difficult to undetstand how the bias window opens up.
In the older versions of ATK I understand it opened up symmetrically (so 1V, the bias window would be from -0.5 to 0.5. Is this the same case for the newer versions? (2022 + ) Or is the bias window now from  0V to eg. 1V and -1V to 0V ?

this is not stated anywhere clear in the tutorials. In the transmission where the fermi level of the electrodes are shown it seems like the window is from 0 to -1V (or +1V) depending on the bias. 
96
General Questions and Answers / Re: How to use workflow iteration for multiple calculation with one calculator?
« Last post by Anders Blom on September 27, 2024, 20:15 »
This issue is fixed in the W-2024.09 release
97
Installation and License Questions / Re: Error in open quantumatk
« Last post by dmicje12 on September 27, 2024, 10:14 »
Thanks!
TSRI give me wrong file .
After I try symbolic link /uesr and /usr , I can open quantumatk!
Thanks again!
98
Installation and License Questions / Re: Error in open quantumatk
« Last post by filipr on September 25, 2024, 17:12 »
Does the executable file /user/cad/synopsys/qatk/2023.12/quantumatk/V-2023.12/atkpython/bin/python3.11 exist? Probably not - most likely you moved the installation of QuantumATK to a different folder: you are trying to run it from the directory /usr/cad/synopsys/qatk/cur (notice even how it's /usr/.. and not /user/...).

You can't move a QuantumATK installation as the launcher scripts (quantumatk and atkpython) hardcode the path to the shipped python executable. So if you moved the QuantumATK installation, either move it back, or delete it and reinstall.

Quote
So,Need I upgrade the python version?

No, QuantumATK is self-contained: it doesn't require any (much) installed software and certainly doesn't depend on other Python installations on the system. It ships its own custom Python interpreter and you can use both side by side without problems (as long as you are careful). For more info see: https://docs.quantumatk.com/manual/Python.html#command-line-usage-with-qatk-shell-environments
99
Installation and License Questions / Error in open quantumatk
« Last post by dmicje12 on September 25, 2024, 15:56 »
Hello,
I am have some problem on opening quantumatk.
My linux version is Centos8 and the python version is 3.6.8
I get atk file from TSRI website
I can source the file which is /usr/cad/synopsys/CIC/qatk.cshrc
But open quantumatk , it have some error, it is like:
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""'
[root@512 synopsys]# quantumatk
/usr/cad/synopsys/qatk/cur/bin/quantumatk: /cad/synopsys/qatk/2023.12/atkpython/ bin/quantumatk: /user/cad/synopsys/qatk/2023.12/quantumatk/V-2023.12/atkpython/bin/python3.11 :bad interpreter: no such file or directory
/usr/cad/synopsys/qatk/cur/bin/quantumatk:line 66: /cad/synopsys/qatk/2023.12/atk python/bin/quantumatk:success
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""'
So,Need I upgrade the python version? , or need I delete all the atk file and install atk again?
Thanks!

100
General Questions and Answers / Re: Plotting fermi surface by tag (like fatbandstructure)
« Last post by Anders Blom on September 25, 2024, 07:30 »
In 3D this would have been harder, but in 2D I think you can do something slightly different since we can use color as a 3rd axis. My suggestion would be to superimpose two contour plots over each other, one for the eigenvalues where you can use lines and just pick the E=0 isoline. Then add another which uses color to indicate the relative contribution of bulk vs surface. This will fill the whole Brillouin zone, but you can see the contributions around the Fermi contour. Use FatBandstructure and project on surface and bulk, respectively, and get the weights from the query function weights(). 
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