Formation Energy, Charged defects, SMW - Reg

[chitrapandy]

I have generated the amorphous IGO (In-Ga-Oxide) configuration and calculated the formation energy for the neutral and charge states in the interstitial defect. I have quite a few structures for this study.
Each structure has a different trap level in the conduction band and varied formation energy (both positive and negative values). I'd like to know what the physical definition of negative formation energy is here. Does obtaining the negative formation energy have any meaning?

One more question:
https://docs.quantumatk.com/tutorials/smw_defects/smw_defects.html
According to this tutorial, we can calculate charged point defects using SMW components. I would make use of this method to calculate the defects associated with my structure. Can you tell me about any tutorials on how to add my structure to this SMW material database and calculate the defects?

[Anders Blom]

Negative formation energy means the compound is stable, positive means it's not,

The "SMW" workflow for computing charged point defects is no longer maintained, and has been replaced by a more flexible framework.
A good starting point is the new manual entry https://docs.quantumatk.com/manual/Types/ChargedPointDefect/ChargedPointDefect.html
You can also see https://docs.quantumatk.com/tutorials/charged_point_defect_study_object/charged_point_defect_study_object.html but it's a bit outdated since it uses the old implementation (still not SMW).
The difference between the SMW flow and the simpler one as described in the tutorial is that the SMW method allowed to extract diffusivity and export that to TCAD tools, whereas the standard interface considered individual defects only. The new framework does however allow for multiple defects now.

[pshinyeong]

Dear Anders,

You mentioned "SMW" workflow for computing CPD is no longer maintained. Does this mean that defect list functions such as vacancy list, substitutional list and transition path list are no longer maintained as well? Or is there another framwork replacing these features.

[Anders Blom]

It is replaced by https://docs.quantumatk.com/manual/Types/DefectDiffusivity/DefectDiffusivity.html. It is not entirely easy to set this up just using scripts, but there are some templates in the Workflow Builder, if you look in the right-hand panel under "Templates > Defects and Defect Diffusion".

We are working on a real tutorial for this.