Queries with AMSET inputs... about amset

[utf]

Hi @rajanpir. Thanks for trying out AMSET.

1. ±1 strain is very large. You can try ±0.05 % instead. You should ensure that you align your eigenvalues to a reference energy, such as the average electrostatic energy at the atomic cores (see LVTOT or LVHAR in vasp).
2. I would suggest calculating the dielectric constant using DFPT. This should be fine except for very small band gap materials (< 0.2 eV), in which case you should use hybrid DFT and the LCACLEPS tag. If you use DFPT you can extract the "effective polar optical phonon frequency" needed in polar optical phonon scattering using the command amset phonon-frequency vasprun.xml where vasprun.xml is the output from the DFPT calculation.
3. For now you should just use the longitudinal spherically averaged elastic constants. But soon I will include the ability to support the full elastic constant tensor.
4. Piezoelectric scattering will only be important if your system belongs to one of the piezoelectric space groups and at low temperatures < 300 K.

Best,
Alex

[rajanpir]

Dear Sir,
Thank you very much... Your suggestions works well for my investigating materials. However, in case of any other crystal system other than cubic (like orthorhombic), how to calculate the longitudinal spherically averaged elastic constants. From aMoBT manual, I have taken the formula to compute the spherically averaged elastic constants for cubic system... In case of other crystal systems how to handle this parameter? Any suggestions from you...? Thanks...