Fyzikální ústav Akademie věd ČR

• materials can be defined using files specifying unit cell
• file extension is expected to be .cell
• by default, the files are saved in subdirectory fzuCommon/cellData/unitCells of the directory, where the CrysTBox is installed to
• file name should reflect file content
• comments are denoted by '#' or '%'
• white characters between lines or individual numbers are ommited

Unit cell properties must be stated in following order:

1. lattice parameter a [nm]
2. lattice parameter b [nm]
3. lattice parameter c [nm]
4. lattice angle alpha [deg]
5. lattice angle beta [deg]
6. lattice angle gamma [deg]
7. material structure ('HCP', 'FCC', 'BCC', Diamond') or by fractional Miller indices of individual atoms in the unit cell written as decimal numbers or fractions
   • in case of Miller indices, one atom must have coordinates [0 0 0]
   • if there is no atom in [0 0 0] coordinates, all atoms are automatically shifted to fulfill this condition
8. atomic numbers - either one number if they are all the same for unit cell atoms, or space-separated values - one per each previously stated atom

File 'Mg HCP.cell' describing Mg HCP unit cell:

# Mg HCP
# Lattice parameters - a, b, c [nm]
0.321
0.321
0.521

# Lattice angles - alpha, beta, gamma [deg]
90
90
120

# Structure
HCP

# Element
12

File 'GaAs.cell' describing unit cell of GaAs compound:

# Lattice parameters - a, b, c [nm]
0.565
0.565
0.565

# Lattice angles - alpha, beta, gamma [deg]
90
90
90

# Positions of atoms in unit cell
[0 0 0]
[0 1/2 1/2]
[1/2 0 1/2]
[1/2 1/2 0]
[1/4 1/4 1/4]
[3/4 3/4 1/4]
[1/4 3/4 3/4]
[3/4 1/4 3/4]

# Element
31 31 31 31 33 33 33 33