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mturiansky / nonrad

Implementation for computing nonradiative recombination rates in semiconductors
https://nonrad.readthedocs.io/en/latest/
MIT License
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Requesting help with a problem for reproducing example #2

Closed iamcqlin closed 2 years ago

iamcqlin commented 2 years ago

Dear all developers or users:

Nonrad is a very powerful code. However, as I am a beginner with nonrad, I had some problems repeating the developer's tutorial.

As a rookie I have tried to repeat this literature "Nonrad: Computing nonradiative capture coefficients from first principles".

I calculated the Configuration Coordinate Diagram , the calculation results look consistent with the example. image

When i calculate the Electron-Phonon Coupling Matrix Element，I found that a large error is produced. The graph I calculated is shown below. image The graph in the example is shown below. image

The process of my calculations is a. Copy the INCAR CONTCAR POTCAR KPOINTS WAVECAR calculated in the "C0" folder to the "WSWQ" folder created in all the folders under the "groud" folder; b. Copy the calculated WAVECAR from all the "groud" folders into their respective "WSWQ" folders and rename them as WAVECAR.qqq; c. Add ALGO=None and LWSWQ=.TRUE to INCAR and do a VASP calculation to get the WSWQ file.

The structure and calculation parameters used for the calculations were taken from https://nomad-lab.eu/. The version of VASP used is 5.4.4. I'm not quite sure if my calculation steps or parameters are correct.

I am wondering if someone could kindly share me the input files and the necessary information about it. I promise they will be used only for research purposed. If it's too much trouble, could anyone send me some relevant information?

Thank you very much for your kind consideration and I am looking forward to your early reply.

Best regards!

Changqing lin

nonrad.zip

mturiansky commented 2 years ago

Hi Changqing Lin,

I believe there is a bug in VASP 5.4.4 where the el-ph matrix element is calculated. Could you try with VASP 6 instead? If not, the bug fix is straightforward. In src/elphon.F, look at the function ELPH_OVERLAP_W_WP. The line that says COVL = 0 needs to be moved after the line that says kpoint: DO NK=1,W%WDES%NKPTS. Let me know if this fixes it or if you have any other questions.

Best, Mark

iamcqlin commented 2 years ago

Hi Mark，

I completed the calculations using vasp 6.3.0 and the results are in good agreement with the literature. But i haven't tested the recompiled vasp5.4.4 yet.

Thank you very much for your kind consideration. Best regards!

Changqing lin

mturiansky commented 2 years ago

No problem. Glad to hear you're using nonrad. Let me know if you have any further questions.

Best, Mark

msehabibur commented 5 months ago

@iamcqlin can you please explain why you chose these KPOINTS:

Manually defined mesh 1 Reciprocal lattice 0.25 0.25 0.25 1

iamcqlin commented 5 months ago

@iamcqlin can you please explain why you chose these KPOINTS:

Manually defined mesh 1 Reciprocal lattice 0.25 0.25 0.25 1

Hi~

The details of my calculations are from the article [Computer Physics Communications 267 (2021) 108056]. 0.25 0.25 0.25 refers to the mean-value point in the Brillouin zone of cubic crystals, as you can learn from the article [Phys. Rev. B 7 (1973) 5212-5215]. This value seems to be limited to cubic cells.

Best Changqing lin

msehabibur commented 5 months ago

Hi, I used your DFT input files to reproduce the defect level, but I got something different. Can you please check your files? @iamcqlin