Grid in ANPHON (KPMODE = 2)

[RicardoCecconello]

Dear Dr. Tadano,

The k grid used in ANPHON (with KPMODE = 2) should be commensurate with the supercell size (i.e., if I use a 4x4x2 supercell, this grid should be 40 40 20 or multiples), or should be commensurate with the dimensions of the primitive cell?

Thanks in advance,
Ricardo.

[ttadano]

Hi,

For the &kpoint field, the k-point grid does not need to be commensurate with the supercell size, unlike the case of KMESH_INTERPOLATE in the &scph field.

However, it is recommended and sometimes necessary (for thermal conductivity calculations) to use a k-point grid that does not break the symmetry of the input lattice. For example, when your supercell is cubic, you should avoid using anisotropic k-point sampling such as 10 10 20.

[RicardoCecconello]

Thank you so much!