quantum-espresso

History

Paolo Giannozzi 6148f5e5c5 Obscure line present in all examples replaced with a much simpler one. See https://stackoverflow.com/questions/50148175/what-does-cd-echo-0-sed-s-1-do-in-bash-script Note: some trailing blanks have been removed as well by the script I used. Use "git diff -b" to see only the true changes.		2022-09-03 11:53:33 +02:00
..
reference	Charge self-consistent DFT+DMFT implementation	2021-10-19 12:17:58 -04:00
README	updating module reference and adding another consistency check of input data	2021-11-22 09:28:09 -05:00
run_example	Obscure line present in all examples replaced with a much simpler one.	2022-09-03 11:53:33 +02:00
srvo3_dmft.h5	Charge self-consistent DFT+DMFT implementation	2021-10-19 12:17:58 -04:00

README

This example shows how to use pw.x to perform DFT+dynamical mean-field
theory (DMFT) calculations charge self-consistently. The formalism
is making use of the interface with Wannier90. The input from DMFT
is given as an hdf5 archive.

The calculation proceeds as follows (for the meaning of the cited input
variables see the appropriate INPUT_* file)

1) make a self-consistent calculation for SrVO3 (input=srvo3.scf.in,
   output=srvo3.scf.out). This is done in the usual manner.

2) make a non self-consistent calculation for SrVO3 (input=srvo3.nscf.in,
   output=srvo3.nscf.out).
   The input variable dmft is set to true so that the code keeps a snapshot
   of the wavefunctions and other quantities for restart at a later time.
   The verbosity must be set to high for the next step (implemented in TRIQS)
   to work properly. The k-points must be given explicitly with nosym set to
   true. The code will notify the user with "Calculation interrupted for call
   of DMFT code" if this step succeeded.

3*)(not done within Quantum Espresso) construct Wannier functions for a
   downfolded model with Wannier90, use the Wannier90 Converter and make a
   DMFT calculation within TRIQS/DFTTools. Obtain charge density updates written
   into hdf5 archive (output=srvo3_dmft.h5)

4) make a "self-consistent" calculation (important: only a single iteration!) for
   SrVO3 (input=srvo3.dmft_scf.in, output=srvo3.dmft_scf.out).
   The run must be called with restart_mode=restart, and with a low mixing_beta
   to achieve convergence in the full DFT+DMFT charge self-consistent cycle.
   The name of the hdf5 archive must be specified as dmft_prefix, and the dmft flag
   must be set to true, which will be documented in the output as:
   "Calculation restarted from a previous run, expecting DMFT hdf5 archive".
   The band window is expected to be read from
   "dmft_prefix.h5/dft_misc_input/band_window", while the occupation updates have to
   be given as "dmft_prefix.h5/dft_update/delta_N".
   With verbosity set to high the updated occupation numbers are printed. 

Steps 2-4) are repeated until convergence of the interacting charge density.

REFERENCES:

S. Beck et al.
Charge self-consistent electronic structure calculations with dynamical mean-field
theory using Quantum ESPRESSO, Wannier90 and TRIQS
arXiv:2111.10289 (2021)

G. Pizzi et al.
Wannier90 as a community code: new features and applications
J. Phys. Cond. Matt. 32 (2020)

O. Parollet et al.
TRIQS: A toolbox for research on interacting quantum systems
Comput. Phys. Commun. 196, 398 (2015)

M. Aichhorn et al.
TRIQS/DFTTools: A TRIQS application for ab initio calculations of correlated materials
Comput. Phys. Commun. 204, 200 (2016)