electron-phonon matrix elements are not hermitian

Discussion around electron-phonon

Moderator: stiwari

Post Reply
simba2828
Posts: 66
Joined: Tue Mar 07, 2023 4:19 pm
Affiliation: IIT Kharagpur

electron-phonon matrix elements are not hermitian

Post by simba2828 »

Dear experts,

From my EPW calculation, the electron-phonon matrix elements at q = 0 are not Hermitian, i.e,

g_{n,m}^\nu ≠ g_{m,n}^\nu*

Could anyone please tell the possible reason?

I am using EPW6.0 where I can print the complex electron-phonon matrix elements.

Sincerely,
Shubham
Shashi
Posts: 71
Joined: Mon Feb 12, 2024 2:21 pm
Affiliation: SUNY Binghamton

Re: electron-phonon matrix elements are not hermitian

Post by Shashi »

Dear Shubham,

You may want to check the behavior at a finite q-point instead of Gamma, since q = 0 can sometimes be special (e.g., degeneracies or phase/gauge issues) that may affect the apparent Hermiticity.

Also, does your system preserve time-reversal symmetry? This can influence the symmetry properties of the electron–phonon matrix elements.

In addition, please check the quality of your Wannierization (e.g., spreads, band interpolation), as poor Wannierization can also lead to such inconsistencies.

It would be useful to verify these points and see if the issue persists away from gamma.

Best regards,
Shashi
Post Reply