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1
Hi,
I have a system whose unit cell has 28 atoms ( 4 magnetic atoms and rest non-magnetic). I fixed spin directions (theta and phi) for all the 28 atoms. My system never reaches to convergence. (Some parameters I put are: initial scaled spins as 0.2 for non-magnetic atoms and 1 for magnetic atoms, fixed_spin_energy=5*eV) Please suggest possible solutions.
Thanks
2
Hi QuantumATK Community,

I hope you are all doing well! I’m new to using QuantumATK (version 2024) and currently trying to learn how to set up and run jobs using the software. I’ve encountered an issue and would greatly appreciate your guidance.

I am attempting to include both 𝐾 and 𝐾′ points in the band structure calculation. While 𝐾 is available as a built-in high-symmetry point, 𝐾′ is not, and when I try to add it manually, I get an error.

Could someone guide me on how to properly add 𝐾′ to the band structure calculation and resolve this issue? Any advice or step-by-step instructions would be greatly appreciated!

Thank you for your help in advance!
3
Plugin Development / QATK 2024-09 IV Curve
« Last post by merlin on February 12, 2025, 13:40 »
Hello everyone,

I previously used the QATK 2022-03 version and have performed current bias voltage calculations. Nowadays, I use the newest version of QATK 2024-09, however, the IVCurve analyzer is absent. Do we need to calculate with the script or can the IV Characteristic study object do this calculation (only current-bias voltage calculation without gate voltage) ? Also, when I obtain the current-bias voltage values via scripting, I cannot plot the result file i.e. IVCurve.hdf5 file as before.

I would be glad if you can help.
4
That's what I was checking, it's often the case that the whole potential doesn't exist under a dedicated name, but each term exists already. But I could not find anything resembling the last term. There are Coulomb terms that are proportional to ZiZj and Lennard-Jones terms which can do 1/r^n, but not the combination. You can still create a tabulated potential yourself, but in my own opinion there is bound to be as good (or better) potentials for SiO2 compared to this one from 1990... A lot of articles have been published since, and there are at least 10 (if not 30) other potentials in QuantumATK for Si+O, including the very popular Tersoff ones, or for glassy materials with partial charges you can try Pedone or some COMB potential.
5
"Thanks for checking. If this functional form isn't directly supported, we might need to explore alternative SiO₂ potentials that QuantumATK can handle. Do you think we could approximate the third term using an existing potential or a combination of supported terms? Otherwise, we might need to consider a custom implementation or another workaround. Let me know your thoughts!"
6
General Questions and Answers / pdos-mpsh
« Last post by Jahanzaib on February 11, 2025, 02:41 »
Dear Expert,

This is my code for MPSH, where I am analyzing atom 112 (Ni) to determine which d-orbitals contribute to the valence and conduction bands. I have also obtained the PDOS and attempted to map the energy levels with the PDOS. I have explored multiple approaches, including this one and some other options. I have attached both the PDOS and MPSH results for reference. my question is - in MPSH, is there a way to adjust the code where we can d-orbital splitting (like which one is dxy etc)
# -------------------------------------------------------------
# Molecular Energy Spectrum
# -------------------------------------------------------------
molecular_energy_spectrum = MolecularEnergySpectrum(
    configuration=configuration,
    energy_zero_parameter=FermiLevel,
    projection_list=ProjectionList(atoms=[112], angular_momenta=[2])
    )
nlsave('MPSH.hdf5', molecular_energy_spectrum)
nlprint(molecular_energy_spectrum)
7
Looks like a reasonable set up but I would definitely make sure it converges with GGA before trying HSE! Also, I have no experience with the Ozaki contour, again I would stick with the simplest option first, i.e. the default contour method. You could try to use fewer history steps, sometimes it works better with say 10 only, but I expect the convergence looks different with GGA, so that is step 1.
8
I couldn't find a matching potential type in our list, so probably it is not easy at all. There are many other SiO2 potentials to choose from, but this functional form is not supported as far as I can tell (the problem is the third term in the two-body potential, we can cover all the other ones).
9
General Questions and Answers / Re: Gold layers in central region
« Last post by Anders Blom on February 11, 2025, 01:41 »
There is no point to make the electrode extension longer than necessary to capture all interactions. That is, once it's long enough that no terms are truncated, making it even longer will have no effect. So make sure the extension is good, then add any additional layers to the central region.
10
Hello, I am trying to calculate transmission spectrum at 0 eV with Silicon/Silicide contact with different doping concentration(5e19,1e20,5e20,1e21)

I tried to converge the LCAO calculator but the device would not converge.

I changed density mesh cutoff, device algorithm(neutral atom, equivalent bulk etc..), contour parameter(ozaki point) for about a week with same structure, but nothing would work.

I tried to solve this problem on my own, but after spending a week with same structure, I realized it was beyond my beyond my capabilities.
Therefore, I have decided to seek assistance.

I am wondering if I am making a mistake or the structure is not properly optimized(0.02eV/A, optimize length : 10A). (I attached txt file of the calculation information)

Can anyone could give me some tips regarding with convergence problem?

When I check the log file, for some reason, the convergence energy suddenly changed to higher value. (40E~42E)

26 E = -940.453 dE =  3.211179e-01 dH =  8.870016e-01                       |
|  27 E = -942.197 dE =  1.744240e+00 dH =  8.995829e-01                       |
|  28 E =  -941.24 dE =  9.571292e-01 dH =  7.565638e-01                       |
|  29 E = -942.876 dE =  1.635776e+00 dH =  8.258672e-01                       |
|  30 E = -943.925 dE =  1.048822e+00 dH =  8.581108e-01                       |
|  31 E =  -944.33 dE =  4.050945e-01 dH =  9.593208e-01                       |
|  32 E = -942.058 dE =  2.272090e+00 dH =  8.716657e-01                       |
|  33 E = -942.011 dE =  4.704906e-02 dH =  8.909611e-01                       |
|  34 E = -941.766 dE =  2.451188e-01 dH =  7.616103e-01                       |
|  35 E = -942.428 dE =  6.625315e-01 dH =  7.147292e-01                       |
|  36 E = -942.211 dE =  2.172081e-01 dH =  6.725936e-01                       |
|  37 E = -942.583 dE =  3.722324e-01 dH =  6.988655e-01                       |
|  38 E = -942.315 dE =  2.688179e-01 dH =  7.281209e-01                       |
|  39 E = -946.068 dE =  3.753141e+00 dH =  7.930580e-01                       |
|  40 E = -944.435 dE =  1.633055e+00 dH =  6.637546e-01                       |
|  41 E =  -961.58 dE =  1.714573e+01 dH =  2.050847e+00                       |
|  42 E = -2420.58 dE =  1.458995e+03 dH =  8.792229e+01                       |
|  43 E = -2558.35 dE =  1.377787e+02 dH =  9.421465e+01                       |
|  44 E = -2414.11 dE =  1.442476e+02 dH =  8.872245e+01                       |
|  45 E = -1620.06 dE =  7.940496e+02 dH =  5.332355e+01                       |
|  46 E = -1685.53 dE =  6.547581e+01 dH =  5.754290e+01                       |
|  47 E = -2391.43 dE =  7.058958e+02 dH =  9.732136e+01                       |
|  48 E = -2297.45 dE =  9.397452e+01 dH =  9.073635e+01                       |
 

Thank you for reading the question
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