How to use cp2k to calculate elastic modulus parameters

[xiao peng]

Hi, everyone

I recently calculated some materials that require computing mechanical properties, such as bulk modulus,  Young's modulus, and shear modulus. But I checked the official website tutorial of cp2k and found that there seem to be no relevant examples.

I would appreciate if you could give me some examples.

Thank you for your time and consideration.
Regards, Peng

[cpash...@gmail.com]

Hi Peng,

If you want to do mechanical properties, the DFPT variant is not implemented in cp2k (last I checked), you will need to compute the stresses and fit the corresponding stresses and strains. One such way is to use the elasticity module available from materials project / pymatgen: https://pymatgen.org/pymatgen.analysis.elasticity.html . Specifically, you should use it to modify the structures (generate the deformations) and fit it. 

Keep in mind that you can't use the wavefunctions to restart at each step because the structure changes. 

Christopher

[xiao peng]

Hi Christopher,

Thank you for your recommendations. As you pointed out, pymatgen can be employed to adjust my structures, and I am now planning to carry out geometry optimizations in batches. However, I find myself unsure about the location of stresses in the output files. Are there specific keywords that need to be configured in my input file to capture this information? Furthermore, can pymatgen assist in the process of fitting stresses and strains appropriately? I would greatly appreciate it if you could provide insights into how this functionality operates.

Thank you once again for your assistance.

Best regards,