Commit 41f7d651 authored by Christoph Friedrich's avatar Christoph Friedrich

Merge branch 'master' of iffgit.fz-juelich.de:spex/spex-docs

(and PLUSSOC updated)
parents 13d7b155 4b84a734
......@@ -163,9 +163,18 @@ As the table can be very large, there is a possibility to choose the atom type i
* - ``BANDINFO 2``
- Restrict the orbital-decomposition table to atom type 2.
.. _ENERGY:
ENERGY
--------
(*) In some cases, it may be necessary to replace the energy eigenvalues, provided by the mean-field (DFT) code, by energies (e.g., *GW* quasiparticle energies) obtained in a previous Spex calculation, for example, to determine the *GW* Fermi energy or to perform energy-only self-consistent calculations. This can be achieved with the keyword ``ENERGY file``, where "file" contains the new energies in eV. The format of "file" corresponds to the output of the ``spex.extr`` utility: ``spex.extr g spex.out > file``. It must be made sure that "file" contains energy values for the whole irreducible Brillouin zone. Band energies not contained in "file" will be adjusted so that the energies are in accending order (provided that there is at least one energy value for the particular k point).
(*) In some cases, it may be necessary to replace the energy eigenvalues, provided by the mean-field (DFT) code,
by energies (e.g., *GW* quasiparticle energies) obtained in a previous Spex calculation, for example,
to determine the *GW* Fermi energy or to perform energy-only self-consistent calculations.
This can be achieved with the keyword ``ENERGY file``, where "file" contains the new energies in eV.
The format of "file" corresponds to the output of the ``spex.extr`` utility: ``spex.extr g spex.out > file``.
It must be made sure that "file" contains energy values for the whole irreducible Brillouin zone.
Band energies not contained in "file" will be adjusted so that the energies are in accending order
(provided that there is at least one energy value for the particular k point).
.. list-table:: Example
:widths: 34 100
......@@ -195,6 +204,17 @@ Spex reads the file "spex.sym" if it exists and "sym.out" otherwise. After the `
Spex run will read the new input data, now including SOC. (The keyword ``PLUSSOC`` must be removed for this new run, otherwise
Spex stops with an error, since it cannot add SOC to a solution that contains it already.)
A possible application of this feature is to add SOC corrections to *GW* quasiparticle energies, already calculated.
To this end, store the *GW* energies to a file using the "spex.extr" utility (example: ``spex.extr g spex.out > energy.inp``).
Then, tell Spex to replace the single-particle energies (that it reads from the input data) by the ones from the file ("energy.inp") with
the keyword ``ENERGY`` (``ENERGY energy.inp``, see :numref:`ENERGY`) and add ``PLUSSOC``. In a subsequent run, Spex will apply the SOC operator to the *GW* quasiparticle
energies using a second-variation technique, write the corrected energies to the output, and write the new input data files.
The latter can be used in a subsequent Spex run, for example, to calculate a Wannier-interpolated band structure,
containing *GW* quasiparticle and SOC corrections. From a theoretical point of view this approach is a bit inconsistent
[Phys. Rev. B 88, 165136 (2013)], but it is considerably faster than running *GW* with SOC from the start. Besides, the
latter approach is currently not applicable to systems with noncollinear magnetism. So, using the present procedure with ``PLUSSOC``
is the only viable approach for this case.
ITERATE
-------
(*) If ``ITERATE`` is specified, Spex only reads the LAPW basis set from the input data, provided by the mean-field (DFT) code,
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment