Bands interpolation does not work with T-rev symmetry

[amolina]

Hello all,

I would like to interpolate the bands but I get an error related to the T-rev symmetry. How can I get rid of that?

Cheers,

Alejandro.

[Daniele Varsano]

Dear Alejandro,
you can try to force to not use the TR symmetries, using the "-t" option in the p2y converter (p2y -t etc. etc.).
Hope it helps,
Daniele

[amolina]

I am trying to remove the TR symmetry but even I put p2y -t I get this:

<---> Symmetries...[SI no]......[-I no]...[TR yes]

Is this flag working properly? maybe something is wrong in the pw.x input file...

Thanks,

Alejandro.

[Daniele Varsano]

Dear Alejandro,
mosto probably this is because you do not have spatial inversion in your system. You can try to check if you can recover it placing your system in the cell in a more symmetric way.
Best,
Daniele

[amolina]

Dear Danielle,

I am afraied this is not possible, one of the characteristic of the system is the absence of inversion symmetry.

[Davide Sangalli]

Ciao Alejandro,
in this case you can remove the time reversal symmetry with ypp (ypp -n)
It is the same tool you will need to run real time simulations.

It generates a new SAVE directory (it is bigger since the Trev is removed). It is not smart to use it for calculations but you can use it for the interpolation.

Best,
Davide

[amolina]

Thanks Davide,

it can work but I get a netcdf error. I will keep trying.

Cheers,

Alejandro.

[Davide Sangalli]

Ok. Try to post error, I'll check it.
D.

[amolina]

OK,

now it works nicely.

I post here the steps I have followed.

p2y -n --------------- Generate the SAVE directory without inversion symmetry
yambo ---------------- Initialize
Copy the ndb.QP file to the new SAVE file
ypp -s b ----------------
Set the variable
GfnQPdb= "E < ./SAVE/ndb.QP"

and that it is!

Alejandro.

[Haichang]

Dear all,
First, I found the new tutorial in
http://www.yambo-code.org/wiki/index.ph ... Structures
cannot be accessed, could you fix it?
Second I am trying to plot the GW band structure of h-BN as the tutorial says, however, even I type
ypp -v
and activated the input: RmTimeRev
I still got a bug report:
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<---> [01] CPU structure, Files & I/O Directories
<---> [02] Y(ambo) P(ost)/(re) P(rocessor)
<---> [03] Core DB
<---> :: Electrons : 8.000000
<---> :: Temperature [ev]: 0.000000
<---> :: Lattice factors [a.u.]: 4.71600 4.08418 33.01200
<---> :: K points : 7
<---> :: Bands : 60
<---> :: Symmetries : 24
<---> :: RL vectors : 21817
<---> [04] K-point grid
<---> :: Q-points (IBZ): 7
<---> :: X K-points (IBZ): 7
<---> [05] CORE Variables Setup
<---> [05.01] Unit cells
<---> [05.02] Symmetries
<---> [05.03] RL shells
<---> [05.04] K-grid lattice
<---> [05.05] Energies [ev] & Occupations

[ERROR] STOP signal received while in :[05.05] Energies [ev] & Occupations
[ERROR] Bands interpolation does not work with T-rev symmetry

I use the newest version which is yambo 4.2.1 . Can anyone tell me how to fix this bug?
Many thanks

Haichang Lu