E.2 Spglib
Spglib is a library for finding and handling crystal symmetries, written by Atsushi Togo (http://spglib.sourceforge.net). FHI-aims can be interfaced to the spglib.
So far, FHI-aims supports the determination of the crystal symmetry for a given (periodic) geometry file and k-point reduction based on this analysis (local and semi-local functionals only). Theoretical background and keywords are described in Section 3.49.
Prerequisites:
spglib is written in C and therefore needs a C compiler with appropriate options in addition to the usual Fortran compiler with which FHI-aims is built.
Ideally the spglib source files should be placed in the folder external/spglib contained within the FHI-aims source (src) directory.
Tag: use_symmetry_analysis(control.in)
Usage: use_symmetry_analysis .true. / .false.
Purpose: This flag activates the interface to the spglib to obtain
symmetry information for the provided geometry file once.
The symmetry information is directly written after the geometry printout
in the FHI-aims standard output. spglib needs to be compiled with FHI-aims
to get the output.
Default: .true.
Tag: sym_precision(control.in)
Usage: sym_precision value
Purpose: This value determines the accuracy for identifying symmetric atoms.
The lower the value, the more strictly the atomic positions must overlap.
Default: