Supercell program: a combinatorial structure-generation approach for the local-level modeling of atomic substitutions and partial occupancies in crystals

Table 1 Comparisons of programs performing combinatorial treatments of disorder in crystals

	supercell	CRYSTAL	SOD	enumlib	eumlib + pymathgen
Public release	2016	2014	2007	2008	2013
License and availability	GPL, open access	Commercial, free demo version available	GPL, on demand	MIT, open access
Programming language	C++	Fortran	Fortran	Fortran	Fortran/Python
Interface	Command line interface (CLI)	Custom configuration file			Python script
Input from standard structure files	Yes	No	No	No	Yes
Preprocessing algorithms	Grouping, occupancy correction	–	–	–	(Any)^a
Non-diagonal supercell expansion matrix	No	Yes	No	Yes
Multinominal distribution	Yes	No	No	Yes
Disorder on several independent sites supported	Yes	No	No	Yes
Random sampling	Yes	Yes	No	No	No
Coulomb energy sampling	Yes	No	No	No	No^b
Interface to calculations programs	External^c	Internal, CRYSTAL only	Internal, VASP, GULP	Internal VASP	Internal VASP, GULP
Performance \(\hbox {Sn}_{0.5}\hbox {Pb}_{0.5}\hbox {Te}\) \(2\times 2\times 2\))^d	27 min	15 s^e	N/A^f	29 h

\(^\mathrm{a}\) Pymathgen supports a wide range of structure manipulation procedures [43]
\(^\mathrm{b}\) Coulomb energy sampling and merge algorithm are mutually exclusive within this framework
\(^\mathrm{c}\) Input for most calculation programs can be prepared with shell scripts and cif2cell or OpenBabel
\(^\mathrm{d}\) The reported time is a dry-run time on Intel^® Xeon^® X5550 processor. All time-consuming I/O operations were disabled. The example is particularly challenging because the number of symmetry operations (1536) is really high (the same number of permutations on systems of lower symmetry should be processed faster)
\(^\mathrm{e}\) The reported duration corresponds to the calculation of the total number of unique structures calculation. The sampling algorithm crashed
\(^\mathrm{f}\) The program crashed with memory error. The expected run time is more than a year

ISSN: 1758-2946