On 06/05/2020 22:02, Shivesh Sivakumar wrote:
Nicola,
Sorry to bring up the subject again but I still can't reconcile
something. I understand that 'U' is not universal and not completely
portable between different PPs. But what I find odd is the effect of
'U'. On QE (with NCPP), 'U' seems to
Nicola,
Sorry for the barrage of messages but it seems like I found the origin of
this odd behaviour. Even though the band structures show very good
agreement (barring the band gap), the contribution of orbitals is different
near VB and CB edges - I did a fatbands calculation on QE and then on
Nicola,
Sorry to bring up the subject again but I still can't reconcile something.
I understand that 'U' is not universal and not completely portable between
different PPs. But what I find odd is the effect of 'U'. On QE (with NCPP),
'U' seems to suppress the band gap whereas in VASP (with PAW),
Nicola,
Thank you very much for your valuable input. It definitely makes everything
more clear to me.
Best,
Shivesh
On Wed, May 6, 2020 at 9:50 AM Nicola Marzari
wrote:
>
>
>
> Dear Shivesh,
>
>
> this is really important: as Iurii and Paolo already mentioned, U is
> *not* a universal
Dear Shivesh,
this is really important: as Iurii and Paolo already mentioned, U is
*not* a universal parameter. For the same element and for the same
material, it can be easily 3eV or 7eV (e.g. if the Hubbard manifold it
acts upon has been taken say from a pseudopotential (NCPP/USPP/PAW)
> http://people.epfl.ch/265334
> --------------
> *From:* users on behalf of
> Shivesh Sivakumar
> *Sent:* Wednesday, May 6, 2020 12:35:30 AM
> *To:* Quantum ESPRESSO users Forum
> *Subject:* [QE-users] Different implementations of the Hubbard 'U'
> between QE
e (EPFL)
> CH-1015 Lausanne, Switzerland
> +41 21 69 34 881
> http://people.epfl.ch/265334
> --------------
> *From:* users on behalf of
> Shivesh Sivakumar
> *Sent:* Wednesday, May 6, 2020 12:35:30 AM
> *To:* Quantum ESPRESSO users Forum
> *Subjec
e, Switzerland
+41 21 69 34 881
http://people.epfl.ch/265334
From: users on behalf of Shivesh
Sivakumar
Sent: Wednesday, May 6, 2020 12:35:30 AM
To: Quantum ESPRESSO users Forum
Subject: [QE-users] Different implementations of the Hubbard 'U' between QE a
Hello all,
While performing PBE+U calculations on a 2-D material, I wanted to try
using NCPPs and then PAW PPs. For the former, I obviously tried QE and for
the latter, VASP. The electronic bandstructures look very similar (the
parameters are completely the same, except for plane wave cutoffs, as
