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###### Perform SOC calculations {#perform_soc_calculations}
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# Perform SOC calculations
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To include spin-orbit coupling (SOC) into the system of study we take
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the scalar-relativistic Hamiltonian and add SOC in the Pauli-form \$
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\\mathcal{H}\_\\mathrm{SO} = \\xi \\, L \\cdot S\$. This is done by the
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new solver. \_\_Note that the new solver works only for spin-polarized
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full potential calculations.\_\_ The features of the old solver like for
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example [DOS](jumu/density_of_states "wikilink"),
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[QDOS](jumu/qdos "wikilink"), or [decimation](jumu/deci "wikilink") work
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the scalar-relativistic Hamiltonian and add SOC in the Pauli-form $`\mathcal{H}_\mathrm{SO} = \xi \, L \cdot S`$. This is done by the
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new solver. **Note that the new solver works only for spin-polarized
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full potential calculations.** The features of the old solver like for
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example [DOS](jumu/density_of_states),
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[QDOS](jumu/qdos), or [decimation](jumu/deci) work
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as usual. The following steps are needed:
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##### Changes in the inputcard {#changes_in_the_inputcard}
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## Changes in the inputcard
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The options //NEWSOSOL// and //fullBZ// have to be set in the inputcard.
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The options *NEWSOSOL* and *fullBZ* have to be set in the inputcard.
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This tells the program to use the new solver and to forget about all
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symmetries previously found for the current setup. This is needed since
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SOC may break some symmetries. In addition some parameters for the
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newsolver have to be set. These are //NPAN\_LOG//, //NPAN\_EQ//,
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//NCHEB// and //R\_LOG//. Also do not forget to do spin-polarized
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calculations for full potential (//NSPIN=2, KSHAPE=2//). If you started
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newsolver have to be set. These are *NPAN_LOG*, *NPAN_EQ*,
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*NCHEB* and *R_LOG*. Also do not forget to do spin-polarized
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calculations for full potential (*NSPIN=2, KSHAPE=2*). If you started
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with a calculation without spin-polarization, i.e. *NSPIN=1*, you can
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[adopt your already converged
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potential](change_nspin_1_to_2 "wikilink"). <code> RUNOPT NEWSOSOL \...
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\...
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+\-\-\-\-\-\--+\-\-\-\-\-\--+\-\-\-\-\-\--+\-\-\-\-\-\--+\-\-\-\-\-\--+
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[adopt your already converged potential](change_nspin_1_to_2).
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```
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RUNOPT
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NEWSOSOL ... ...
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+-------+-------+-------+-------+-------+
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` ***test options*** (2 lines) `
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TESTOPT fullBZ
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+\-\-\-\-\-\--+\-\-\-\-\-\--+\-\-\-\-\-\--+\-\-\-\-\-\--+\-\-\-\-\-\--+
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+-------+-------+-------+-------+-------+
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\...
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...
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NSPIN=2
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\...
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...
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KSHAPE=2
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\...
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...
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HFIELD= 0.0 VCONST= 0.0d0 NPAN\_LOG= 15 NPAN\_EQ= 5 NCHEB= 12 R\_LOG=
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HFIELD= 0.0 VCONST= 0.0d0 NPAN_LOG= 15 NPAN_EQ= 5 NCHEB= 12 R_LOG=
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1.0d0
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BZDIVIDE= 30 30 30
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\... </code> If the new solver without SOC should be used the test
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option //NOSOC// has to be added.
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...
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```
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If the new solver without SOC should be used the test
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option *NOSOC* has to be added.
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##### additional input files {#additional_input_files}
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## additional input files
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Since the new solver does also deal with non-collinear calculations we
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have to specify the non-collinear angles of each atom in the inputcard
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in the file [nonco\_angle.dat](jumu/nonco_angle.dat_file "wikilink"). If
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in the file [nonco_angle.dat](jumu/nonco_angle.dat_file). If
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this file is not given then the angles are fixed to theta=phi=0 (i.e.
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the z-direction).
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##### Examples
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## Examples
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#### Example 1: bulk Au with and without SOC {#example_1_bulk_au_with_and_without_soc}
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### Example 1: bulk Au with and without SOC
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As an example the difference between bulk Au with and without SOC should
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be calculated. The test system consists of bulk Au (fcc lattice) with a
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| ... | ... | @@ -65,14 +67,15 @@ LMAX cutoff set to 2 and a k-mesh of 15x15x15, for the sake of speed of |
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the calculation.
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`{{:jumu/examples:au_bulk_nosoc_cos.tar.gz|Here}}`{=mediawiki} the input
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files of both cases with the different inputcards can be found. Using
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the [QDOS](jumu/qdos "wikilink") the change in the band structure can be
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the [QDOS](jumu/qdos) the change in the band structure can be
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investigated.
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#### Example 2: bulk Au with and without SOC {#example_2_bulk_au_with_and_without_soc}
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### Example 2: bulk Au with and without SOC
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The second example is the SOC-induced splitting of Au(111) surface
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states using a half-infinite Au(111) crystal (using the
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[decimation-technique](jumu/deci "wikilink")) and the
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[QDOS](jumu/qdos "wikilink") option. \<WRAP center round todo 60%\> Add
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example files with instructions, also to [examples
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page](jumu/examples_and_tips "wikilink"). </WRAP> |
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[decimation-technique](jumu/deci)) and the
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[QDOS](jumu/qdos) option.
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## TODO
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Addexample files with instructions, also to [examples page](jumu/examples_and_tips). |
