Dear Alex,

I have a question related to the deformation potential constant.

While calculating the deformation potential, what reference energy

state was considered while calculating the change in the absolute band

positions as a function of strain? This reference state can be very

crucial in determining the deformation potential.

Please make a reference to Fermi Level. I have double checked it.

Dear GAO,

Thank you for your reply. Can you explain in more detail? How you take the Fermi level as a reference?

Hi Aamir,

In the `amset deform`

tool, there are three potential reference levels depending on the system and the calculation settings:

For semiconductors/insulators (i.e., when the band gap != 0), the reference level is taken from either:

- The average electrostatic potential at the atomic cores (written by default in the OUTCAR). The average value across all atoms is used as the reference.
- The core level eigenvalues (used if
`ICORELEVEL = 1`

). Again, the average value for all atoms is used. For each atom, the deepest core level is chosen.

For metals:

- In metals the Fermi level is used as the reference. See Khan and Allen, Phys. Rev. B, 29 (1984) 3341 for more details.

I hope that answers your question.

Best,

Alex

Dear Aamir,

Especially, the energy is E-Ev. Ev is the absolute value of the vacuum. the x-axis is the delta_strain/L0. L0 is the unstrain length. Then you can use a linear fit to get the deformation potential constants as you like. More details can be found: DOI: 10.1021/acsami.8b11836

Best wishes,

Zhibin