[Wannier] Integrals over 1 or 2 MLWF's

[elchatz at auth.gr]

Hello all,

I am also looking at a similar problem now (that is overlap integrals  
between two WFs <u_n|n_m>) and wondering if you had any luck with it.

The only difference is that I am working with projected and not MLWFs.

If I understand correctly, the Amn matrix is the projection of the  
Bloch functions on the trial orbitals. In the case of disentanglement,  
this array may be similar to the truncated Unk array inside the frozen  
energy window. I have also found in one reference (Marzari 2012) that  
the overlap matrix for the Bloch states = (A_k^dagger A_k)_mn, but to  
get the overlaps for the WFs from this array, may still involve some  
extra operations.

I was wondering if the fact that I am doing no minimization of the  
spread means that the states are non-orthogonal, and if there is a  
faster way to get the orbital overlaps from somewhere in the code,  
that I can print out.

Can someone comment on any of these?

Regards,

Eleni

-- 
Dr. Eleni Chatzikyriakou
Laboratory of Theoretical and Computational Solid-State Physics
Aristotle University of Thessaloniki
https://nanobuff.wordpress.com/