Qusetions about the elastic constants and deformation potential used for 2D materials in AMSET

AMSET
1

Dear Alex:
I hope this finds you well! Now I am intended to calculate the mobility of 2D polar materials using AMSET, where a slab model with a 2D/vacuum superlattice is used. As the AMSET is designed for 3D bulk materials, we must make some corrections to the inputs of AMSET, e.g., the elastic constant and deformation potentials. Following are my questions:

  1. Regarding the elastic constant matrix, there are five independent elements( including C11, C12, C13, C33, C44) and two independent elements (including C11, C12) for the 3D and 2D materials respectively with the same Hexagonal lattice. So should the matrix used in the Amset be replaced by the 2D one instead of that calculated from DFPT. Is it true?

  2. The deformation potential used in AMSET relies on the shift in energies: Dnk,αβ=δεnk/Sαβ, which means that the deformation potential should not depend on the vacuum used in the model. However, I wonder if AMSET can correctly identify the crystal symmetry to generate the deformations for the 2D system? In addition, for a system where VBM or CBM is in a degenerate state, what is the appropriate input format for the deformation matrix?

Thanks and any help will be greatly appreciated.
Best,
Leesen

2

Dear Leesen,

I came across your detailed question from 2022 about using AMSET to calculate mobility of 2D polar materials. I’m currently trying to do the same for a 2D polar system (slab model with vacuum, modifying elastic constants, deformation potentials, etc.).

I was wondering if you ever managed to get reasonable results with AMSET for 2D materials? If yes, would you be willing to share your settings (e.g., how you handled the elastic constant matrix, dielectric tensor, and deformation potential for degenerate bands)?

Any advice or sample input would be greatly appreciated.

Thank you very much!