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lucydot / effmass

Calculates various definitions of effective mass from the electronic bandstructure of a semiconductor.
https://effmass.readthedocs.io/en/latest/
MIT License
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inconsistent segments #47

Closed ghost closed 1 year ago

ghost commented 3 years ago

Hi,

I'm using effmass module to determine the effective masses of some layered materials. However, there is a problem that I could not find a solution yet. I'd appreciate your help and suggestions.

When I plot effective masses in different directions for different HfS2 bulk systems (optimized with different levels), efmass shows a segment that does not available in other plot. All band structure calculations were performed using FHI-aims with HSE06+SOC level. The first plot shows effmass plot for HSE06+SOC@PBE+D3 and the second one shows for HSE06+SOC@PBE+D4. image image Because of that reason effective masses in directions [100] and [110] are incomparable. Thanks in advance

lucydot commented 3 years ago

Hi @ebirkan,

It looks that in your second plot the maxima has been shifted away from gamma and now sits along the G-M line - difficult to say without data but there could be a little "kink" in the G-M line. Effmass defines a maxima as a point with two lower energy points either side - it is no more clever than that!

If that is the case then effmass is working as expected (correct me if I'm wrong) and is reflecting your DFT calculated dispersion (you could verify this by looking at the energies in your data directly).

If the "kink" is there then how you deal with that will depend on the context of the problem, perhaps a question better suited to members of your research group or collaborators.

ghost commented 3 years ago

Thanks for the comment and suggestions. I'll follow your suggestions

lucydot commented 2 years ago

Hi @ebirkan - did you solve the issue you were having? If so, I will close this discussion.