Obtaining Piezoelectric Stress Tensor for a Strained Monolayer with GGA+SOC by DFPT
Posted: Mon Jul 17, 2023 7:46 am
Dear users and developers, (I submitted the same post just a while ago but did not zip all the required files and hence I am resubmitting it)
I have been trying to obtain the piezoelectric stress tensor for monolayer CaAlGaSe4 at 6% tensile strain as reported using DFPT with GGA+SOC in the following paper:
https://doi.org/10.1039/D1TC01165K
My goal is to benchmark my method by trying to reproduce the results reported in the aforementioned paper, since I am also working on a strained monolayer that has potential for piezoelectric applications.
I have followed the following steps for obtaining the piezoelectric stress tensor for CaAlGaSe4 at 6% tensile strain:
1. I optimized the unstrained structure. I optimized the structure in all three dimensions, and did not restrict the change of cell parameter along the z-axis using any patch during compilation of VASP.
2. I applied 6% tensile strain to the structure and then relaxed it using fixed-cell structural optimization.
3. I formed an orthorhombic supercell by transforming the structure obtained in the previous step (as also done in the ref. paper).
4. I tried to obtain the piezoelectric stress tensor for the structure obtained in step-3 with GGA+SOC by DFPT. The POSCAR, INCAR and KPOINTS files used for this step and the corresponding OSZICAR, OUTCAR and stdout files are provided in the .zip file attached. The k-points, EDIFF, ENCUT have been set according to those used in the reference paper.
After following these steps, I obtained e11 = 3.3757e-10 C/m (Reference: 3.071e-10 C/m) and e31 = 0.1015e-10 C/m (Reference: -0.066e-10 C/m). It is worth mentioning that the "linear response to electric field" calculation for directions 1 and 3 was stuck at a certain low accuracy till the very end (You could see them if I was able to attach the OSZICAR, log.txt), which comes off to me as a warning that something is not right.
My results are far off from the results reported and hence I tweaked some parameters and re-ran my calculations but I have not been able to obtain reliable results so far. As such, I am at a loss as to what I have been doing wrong.
Under the circumstances, I would be extremely grateful if someone could kindly help me out by pointing out what I should change in my method or in the input tags so as to obtain the correct results. I would very much appreciate any kind help.
I have been trying to obtain the piezoelectric stress tensor for monolayer CaAlGaSe4 at 6% tensile strain as reported using DFPT with GGA+SOC in the following paper:
https://doi.org/10.1039/D1TC01165K
My goal is to benchmark my method by trying to reproduce the results reported in the aforementioned paper, since I am also working on a strained monolayer that has potential for piezoelectric applications.
I have followed the following steps for obtaining the piezoelectric stress tensor for CaAlGaSe4 at 6% tensile strain:
1. I optimized the unstrained structure. I optimized the structure in all three dimensions, and did not restrict the change of cell parameter along the z-axis using any patch during compilation of VASP.
2. I applied 6% tensile strain to the structure and then relaxed it using fixed-cell structural optimization.
3. I formed an orthorhombic supercell by transforming the structure obtained in the previous step (as also done in the ref. paper).
4. I tried to obtain the piezoelectric stress tensor for the structure obtained in step-3 with GGA+SOC by DFPT. The POSCAR, INCAR and KPOINTS files used for this step and the corresponding OSZICAR, OUTCAR and stdout files are provided in the .zip file attached. The k-points, EDIFF, ENCUT have been set according to those used in the reference paper.
After following these steps, I obtained e11 = 3.3757e-10 C/m (Reference: 3.071e-10 C/m) and e31 = 0.1015e-10 C/m (Reference: -0.066e-10 C/m). It is worth mentioning that the "linear response to electric field" calculation for directions 1 and 3 was stuck at a certain low accuracy till the very end (You could see them if I was able to attach the OSZICAR, log.txt), which comes off to me as a warning that something is not right.
My results are far off from the results reported and hence I tweaked some parameters and re-ran my calculations but I have not been able to obtain reliable results so far. As such, I am at a loss as to what I have been doing wrong.
Under the circumstances, I would be extremely grateful if someone could kindly help me out by pointing out what I should change in my method or in the input tags so as to obtain the correct results. I would very much appreciate any kind help.