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Messages - Anders Blom

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31
Right, we seem to be missing a simple transmission plotter for this...

I managed to work around it in a not-so-pretty way. You can use the Data plot tool instead to make each individual transmission plot, then combine the two plots by dropping one plot on the other. If you need step-by-step instructions, let me know and I'll add it below.

32
That depends a bit on what you mean by Fermi level here.

If you are talking about the number reported in the log file sometimes, it's a meaningless quantity that cannot be used for anything except (internally) to set the reference level for other energies, whose difference compared to this energy is meaningful of course.

If you mean how we determine the zero level for band structure plots, this is simply the level which makes the Fermi function integrate to the correct number of electrons. Note that the default electron temperature (1000 K) sometimes means this level is not exactly in the middle of the band gap for semiconductors. The high number means convergence is quicker, but not as accurate.


33
It's both really easy and perhaps a bit confusing for old users how to do this now :)
Just select the two data sets you want to compare, then click the first icon under "Open" in the right-hand panel.

34
It will not affect any results as it will just result in a constant drift of all atoms. Unless of course some atoms are suspended and don't "fall", but even so we are talking about an effect maybe 10^30 times smaller than anything else so why bother - we don't have enough decimals the floating point representation of the computer to even add such numbers together...

Anyway, here is an example of how to use hook functions: https://docs.quantumatk.com/manual/Types/StrainConfigurationHook/StrainConfigurationHook.html


35
Then it's easier, just basically just need GeometryOptimization with DFT, possibly with the rigid body constraint as used in the DeviceOpt algorithm. See the tutorial for underlying details.

36
I think you need to go back to the setup of the initial NEB trajectory, it doesn't look correct, the atoms are moving all over the place. For a NEB calculation to be successful (and mean something) you basically want most atoms to remain at or close to the same position, and only some particular atoms to move. Might be that the indices of the atoms have become mixed up, but best to go back to the initial idea and set it up properly.

37
Only DFT. I am not aware of any semi-empirical parameter sets for those materials.

38
99% of cases like this is because your computer ran out of memory. Phonon calculations can be extremely resource-demanding unless you carefully tune the computational parameters, esp. if you use automatic determination of the supercell size (and even worse if the system is large to begin with). We cannot comment further without details of the calculation though.

39
To our great disappointment it seems the Iris drivers have some general problems for software like ours. NanoLab is not the only program affected, and it's not easy to solve. We are investigating further but also hope Intel might fix this in a driver update.

The only real work-around for now is to turn off shaders in Preferences, but unfortunately this removes some functionality and makes the 3D slower.


40
sets[0].configurations() should do it (returns a Trajectory)

Please check the documentation of classes in the reference manual, usually you can find the answer there quicker than asking on the Forum :-)
https://docs.quantumatk.com/manual/Types/TrainingSet/TrainingSet.html

41
Unless I am mistaken, the transmission matrix should be Hermitian, thus the DownUp component would just be the complex conjugate of UpDown

42
Thanks for letting us know in such detail! I assume you modified this line yourself to fix the problem, but we can definitely look at including this in future updates.

43
The matrix should be square already

44
What is the source of the utilities.py script, is it from some tutorial?

Try replacing it with
builder.createHamiltonianCalculator()
but if we changed that name, maybe other things in this script will break too. This is not officially supported functionality (which is why we change it between versions sometimes, when we restructure the code) but if this provides some useful functionality for you, let us know where you got the script, probably it needs to be updated.

45
It should still work but the interface looks a bit different now. I strongly recommend having a look at https://www.youtube.com/watch?v=v9dtTCGWnqo and the manual page http://docs.quantumatk.com/tutorials/data_view/data_view.html

Now, I don't have QE output data at my fingertips to test with, but I believe that the reason the data doesn't pop up in the Data View is that the QE filters are not enabled by default. You can turn them on by clicking the "pen" icon in the field Data Sources, then open up the Inspectors dropdown, and tick the QE filters.

Hope that works, else share the files so we can investigate further.

And yes, the tutorial should be updated!

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