[ase-users] [gpaw-users] Wannier function calculations

[Mikkel Strange]

Hi Miguel,

I'll try to answer some of the questions.

Q1 and Q2:
The GPAW and ASE Wannier modules are not identical.
GPAW's only works with occupied states while ASE's can deal with entangled bands to generate partly occupied Wannier functions.

Q3:
Don't know.

Q4:
The get_pdos function simply gives  projected density of state onto a Wannier function |w>:
pdos(E) = sum_kn |<psi_kn | w>|^2 dirac_delta(E - e_kn),
where |psi_kn> is the eigenstates and dirac_delta is the delta function which is approximated by a gaussian in the code.

Best
Mikkel

________________________________
From: gpaw-users-bounces at listserv.fysik.dtu.dk [gpaw-users-bounces at listserv.fysik.dtu.dk] on behalf of Miguel Caro [miguel.caro at aalto.fi]
Sent: Thursday, March 24, 2016 5:04 PM
To: ase-users at listserv.fysik.dtu.dk; gpaw-users at listserv.fysik.dtu.dk
Subject: [gpaw-users] Wannier function calculations

Hi all,

I'm going to try some Wannier function calculation with ASE/GPAW and wanted to ask a couple of questions. Hopefully somebody knows the answers.

About the code:

1) I see that there are two different implementations, one in ASE (from ase.dft import Wannier) and another one in GPAW (from gpaw.wannier import Wannier). Are they equivalent?

2) Can these classes be used to obtain Wannier functions when "entangled" bands are involved?

3) I encountered an issue with (lack of) implementation of Wannier function calculation for non-orthorhombic cells when using the class from gpaw.wannier (I haven't tried the ASE class yet), is this solved in e.g. the development version?

About the science:

4) I see that with the ASE class one can calculate PDOS [get_pdos()] for specific Wannier functions. What is the physical interpretation of this, if there is any? Could one interpret \int dE E PDOS(E) as the "effective" energy of a hypothetical electronic state which looks the same as the corresponding Wannier function?

Many thanks in advance!

Miguel
--
Dr. Miguel Caro
Postdoctoral researcher
Department of Electrical Engineering and Automation,
and COMP Centre of Excellence in Computational Nanoscience
Aalto University, Finland
Personal email: mcaroba at gmail.com<mailto:mcaroba at gmail.com>
Work: miguel.caro at aalto.fi<mailto:miguel.caro at aalto.fi>
Website: http://mcaroba.dyndns.org
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