2.0 KiB
| authors |
|---|
| MG |
First tutorial on GWR (GW in real-space and imaginary time)
The quasi-particle band structure of Silicon in the GW approximation.
This tutorial aims at showing how to calculate self-energy corrections to the DFT Kohn-Sham (KS) eigenvalues in the on-shot GW approximation using the GWR code
The user should be familiarized with the four basic tutorials of ABINIT, see the tutorial home page.
This tutorial should take about 2 hours.
WARNING : THIS TUTORIAL IS WORK IN PROGRESS ! IT IS NOT YET COMPLETE ...
[TUTORIAL_README]
Ground-state computation
The first dataset produces the density file that used to compute the band structure in the second dataset. We will also use this DEN file to generate the WFK with empty states in the next section.
Generation of the WFK file with empty states
###########################################
# Dataset 2: Direct diago with empty states
###########################################
optdriver2 6 # Activate GWR code
gwr_task2 "HDIAGO" # Direct diagonalization
getden2 1
nband2 40 # Number of (occ + empty) bands
!!! important
gwr_task2 "HDIAGO_FULL"
The direct diagonalization is MPI-parallelized across three different levels:
collinear spin \sigma, k-points and scalapack distribution of the H^\sigma_\kk(\bg,\bg') matrix.
Abinit will try to find an optimal distribution of the workload at runtime yet there are a couple
of things worth keeping in mind when choosing the number of MPI processes for this step.
Ideally the total number of cores should be a multiple of nkpt * nsppol to avoid load imbalance.
QP corrections with GWR
The k-points for the QP corrections can be specified in different ways.
Explicitly via:
Implicitly via gw_qprange
For the spectral function
Notes on the MPI parallelization
The GWR code employs gwr_np_kgts. Ideally the total number of MPI processes should be a multiple of gwr_ntau * nsppol.