Dear all,
I recently did DFT calculation and Wannier interpolation for the band structure of a janus monolayer (SOC was considered). In general, the obtained DFT band structure and Wannier band structure are similar. However, there is a Rashba-like splitting at the valence band maximum (VBM) of the Wannier band structure while there is no splitting at the VBM of the DFT band structure, for the same janus monolayer.
I have tried to recalculate the DFT band structure with larger k-points and the result is still the same, no splitting at the VBM of the DFT band structure.
Has anybody met the same issue? I would appreciate any suggestions or inputs. Thank you in advance.
Hello Dr. Saharan, thank you for the insight.
The Wannier band structure and the DFT band structure are already plotted within the same k-path. In general, at glance, the band structures are similar. But, there is a Rashba-like splitting at the VBM of the Wannier band structure while there is no splitting at the VBM of the DFT band structure, at Gamma-point. I wonder if I missed something on the DFT calculation or on the Wannier interpolation. The plot comparison is attached.
Again, thank you for your kind response.
It is not uncommon for the band structure obtained from DFT calculations to be different from that obtained from Wannier interpolation, even for the same material. This can be due to various factors, such as the choice of exchange-correlation functional, the k-point sampling, or the treatment of spin-orbit coupling (SOC).
Regarding the Rashba-like splitting at the valence band maximum (VBM) of the Wannier band structure but not in the DFT band structure, it could be caused by the following reasons:
In general, it is not possible to say for sure what the reason for the discrepancy between the DFT and Wannier band structures is without further analysis of your specific system and calculations. I would recommend comparing the results with other theoretical and experimental studies
Dear Prof. Vajeeston,
Thank you for the very detailed explanation. I have tried to increase the k-points, your third point, but in this case it seemed not working. Or maybe, a much higher value is required.
I will try to evaluate all your points one by one and I will give the update here if possible.
Your input is highly appreciated.
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