Yambo Community Forum

Posted: **Thu Aug 20, 2015 3:20 pm**

Hi

I have recently used yambo 4.0.1 to calculate the EELS data of certain material, which obviously respect time-reversal symmetry. But as I use p2y to generate database from the wavefunctions of PW.x, I have found the following information

<03m-12s> :: Symmetries [spatial]: 12
<03m-12s> :: [T-rev]: no

Also, as I type the command yambo to initialize, I have got the following info

[SYMs] K-space Time-reversal not included
[SYMs] Spatial inversion 7 is a symmetry
[SYMs] Group table built correctly

Just of curiosity, I would like to know why the time-reversal symmetry is not recognized in yambo. Or maybe it is pw.x that breaks the symmetry somehow?
Could you please help me explain this?

Thank you very much.

Posted: **Mon Aug 31, 2015 2:51 pm**

Dear Wen-Dong Cao,
p2y looks for what pw.x wrote inside the jobname.save folder.

In particular it uses the pw.x iotk library and does the call:

Code: Select all

CALL iotk_scan_dat( iunit, "TIME_REVERSAL_FLAG", trevsym_, IERR=ierr )

Based on the result (trevsym_ = .true. or trevsym_=.false ) you get the message in output.

Best,
D.

Posted: **Mon Sep 07, 2015 10:25 pm**

Thank you very much.

So this is the problem of my pw.x calculations.

Yambo Community Forum

p2y [T-rev]: no

p2y [T-rev]: no

Re: p2y [T-rev]: no

Re: p2y [T-rev]: no