mirror of https://gitlab.com/QEF/q-e.git
59 lines
2.6 KiB
Plaintext
59 lines
2.6 KiB
Plaintext
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This example shows how to use pw.x to perform DFT+dynamical mean-field
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theory (DMFT) calculations charge self-consistently. The formalism
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is making use of the interface with Wannier90. The input from DMFT
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is given as an hdf5 archive.
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The calculation proceeds as follows (for the meaning of the cited input
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variables see the appropriate INPUT_* file)
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1) make a self-consistent calculation for SrVO3 (input=srvo3.scf.in,
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output=srvo3.scf.out). This is done in the usual manner.
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2) make a non self-consistent calculation for SrVO3 (input=srvo3.nscf.in,
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output=srvo3.nscf.out).
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The input variable dmft is set to true so that the code keeps a snapshot
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of the wavefunctions and other quantities for restart at a later time.
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The verbosity must be set to high for the next step (implemented in TRIQS)
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to work properly. The k-points must be given explicitly with nosym set to
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true. The code will notify the user with "Calculation interrupted for call
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of DMFT code" if this step succeeded.
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3*)(not done within Quantum Espresso) construct Wannier functions for a
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downfolded model with Wannier90, use the Wannier90 Converter and make a
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DMFT calculation within TRIQS/DFTTools. Obtain charge density updates written
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into hdf5 archive (output=srvo3_dmft.h5)
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4) make a "self-consistent" calculation (important: only a single iteration!) for
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SrVO3 (input=srvo3.dmft_scf.in, output=srvo3.dmft_scf.out).
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The run must be called with restart_mode=restart, and with a low mixing_beta
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to achieve convergence in the full DFT+DMFT charge self-consistent cycle.
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The name of the hdf5 archive must be specified as dmft_prefix, and the dmft flag
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must be set to true, which will be documented in the output as:
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"Calculation restarted from a previous run, expecting DMFT hdf5 archive".
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The band window is expected to be read from
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"dmft_prefix.h5/dft_misc_input/band_window", while the occupation updates have to
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be given as "dmft_prefix.h5/dft_update/delta_N".
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With verbosity set to high the updated occupation numbers are printed.
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Steps 2-4) are repeated until convergence of the interacting charge density.
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REFERENCES:
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S. Beck et al.
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Charge self-consistent electronic structure calculations with dynamical mean-field
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theory using Quantum ESPRESSO, Wannier90 and TRIQS
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arXiv:2111.10289 (2021)
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G. Pizzi et al.
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Wannier90 as a community code: new features and applications
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J. Phys. Cond. Matt. 32 (2020)
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O. Parollet et al.
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TRIQS: A toolbox for research on interacting quantum systems
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Comput. Phys. Commun. 196, 398 (2015)
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M. Aichhorn et al.
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TRIQS/DFTTools: A TRIQS application for ab initio calculations of correlated materials
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Comput. Phys. Commun. 204, 200 (2016)
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