quantum-espresso/KCW/kcw.md

project: KCW src_dir: ./src output_dir: ./Doc_ford summary: KCW is an open-source F90/MPI code which calculates spectral properties using the koopmans-compliant framework and Maximally Localized Wannier Functions. authors: Nicola Colonna Riccardo de Gennaro Edward Linscott Nicola Marzari predocmark: > docmark_alt: # predocmark_alt: < display: public private graph: true source: false

NOTABENE To generate the automatic FORD documentation: "ford -I ../LAXlib kcw.md"

KCW stands for "Koopmans-compliant functionals in a Wannier representation". KCW is an open-source F90/MPI code which calculates quasiparticle energies of finite and extended systems using Koopmans-compliant functionals and Maximally Localized Wannier Functions. The details of this implementation are described here (see also here for the arXiv version). The code consists of 3 main modules specified by the "calculation" variable in the CONTROL namelist:

1. interface between PWscf, and Wannier90 and the KCW code (calculation="wann2kcw")

2. calcuation of the screening coefficients (calculation="screen")

3. calculation, interpolation and diagonalization of the KC hamiltonian (calculation = "ham")

Finally "calulation=cc" computes the (estimated) q+G=0 contribution to the bare and screened KC corrections. A report on this quantities is printed on output and can be used to correct a posteriori a calculation performed without any corrective scheme (l_vcut=.false.)

KCW is developed and maintained by Nicola Colonna, Riccardo de Gennaro, and Edward Linscott

TODO list: 
1) Symmetry: at the moment no symmetry are used. 
This was primarely because W90 works on a regular mesh of k points and 
does not account for symmetry. Prob need W90 to work in the IBZ.
2) Initialize the xc-kernel and KC response as the spin-polarized one 
also when nspin=1. This is needed to correctly define the perturbing
potentials. At the moment we do a nspin=2 calculation from the beginning
(not a big deal since the bottleneck is the LR calculation for which in 
    any case a spin-polarized response is needed).