Author Topic: Can not repeat the result of piezoelectric coefficients of example GaAs  (Read 265 times)

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Offline arlonne

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Dear all,

 I am attempting to repeat the result of the example  of piezo_GaAs.py (in Page 723 of Reference-Manual, Release 2017.2). Below is my result with 2017.2 version QATK:
"
+------------------------------------------------------------------------------+
| Piezoelectric Tensor Report                                                  |
+------------------------------------------------------------------------------+
|                                                                              |
| Tensor in units of [C/m**2]:                                                 |
|                                                                              |
|           x              y              z                                    |
| xx    4.05800e-01    9.68754e-01    1.02461e+00                              |
| yy    1.67280e-01   -2.57980e+00    1.91885e+00                              |
| zz    1.46679e+00    1.32262e-01    5.77928e-01                              |
| yz   -1.71568e+00    9.27315e-03    9.77441e-03                              |
| xz    9.27315e-03   -9.92013e-01    9.27315e-03                              |
| xy    9.77441e-03    9.27315e-03   -1.43153e+00                              |
|                                                                              |
+------------------------------------------------------------------------------+
"
And this is the result in Page 273:
"
+------------------------------------------------------------------------------+
| Piezoelectric Tensor Report |
+------------------------------------------------------------------------------+
| |
| Tensor in units of [C/m**2]: |
| |
| x y z |
| xx 2.01774e-12    1.27223e-12    1.18732e-12 |
| yy 2.86045e-13   7.92764e-13   5.13819e-13 |
| zz 9.78384e-13   4.45648e-13  -2.59427e-13 |
| yz -8.28198e-01  1.48791e-13  -9.55916e-14 |
| xz 1.17508e-13     -8.28198e-01   7.05227e-14 |
| xy 1.28983e-13      3.64354e-14   -8.28198e-01 |
| |
+------------------------------------------------------------------------------+
"
You can see that they are totally different!!! So, what's wrong?
I appreciate your help! Thanks.

Offline Nordland

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Are you running the exact same script from the manual?

Offline F. Fuchs

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I just tried to reproduce the piezoelectric tensor from the manual (https://docs.quantumatk.com/manual/Types/PiezoelectricTensor/PiezoelectricTensor.html) as well. I am using version Q-2019.12. The result I got also disagrees with the manual. There is also different to what arlonne has posted earlier.
And yes, I just copied and pasted the input script from the manual.

Maybe some defaults have been changed from version to version? An update of the manual would be nice in this case.

The result I got is also wrong in the sense that the xx, yy, zz components are not zero. Thus, I suppose that the input script in the manual requires more precise DFT parameters.

Regards,
Florian


Result with Q-2019.12 using the input file from https://docs.quantumatk.com/manual/Types/PiezoelectricTensor/PiezoelectricTensor.html
+------------------------------------------------------------------------------+
| Piezoelectric Tensor Report                                                  |
+------------------------------------------------------------------------------+
|                                                                              |
| Tensor in units of [C/m**2]:                                                 |
|                                                                              |
|           x              y              z                                    |
| xx    7.44784e-01    9.67739e-01   -7.44377e-02                              |
| yy   -7.44414e-02    1.83366e-01   -7.44846e-02                              |
| zz   -7.44414e-02    9.67739e-01   -8.62789e-02                              |
| yz   -1.87937e+00   -7.51877e-04   -2.50626e-04                              |
| xz   -7.51875e-04   -1.33056e+00   -7.51877e-04                              |
| xy    9.77514e-03    9.26680e-03    2.69444e+00                              |
|                                                                              |
+------------------------------------------------------------------------------+
« Last Edit: November 20, 2020, 09:46 by F. Fuchs »