Unit cell

The group contains the definition of the lattice basis vectors and the position of atoms within the unit cell. By default the atomic positions are in fractional coordinates

parameter

Lattice parameter in meters.

basis

Matrix of lattice vectors in the format:

basis = (
 [a1, b1, c1],
 [a2, b2, c2],
 [a3, b3, c3]);

Note

The basis vectors form the columns of this matrix, not the rows.

positions

Position of atoms in the unit cell (fractional coordinates by default).

coordinate_format = "fractional"

“fractional” or “cartesian”

Coordinate format for the positions setting.

Example

unitcell: {
    parameter = 0.3e-9;

    basis = (
     [1.0, 0.0, 0.0],
     [0.0, 1.0, 0.0],
     [0.0, 0.0, 1.0]);

   positions = (
    ("A", [0.00, 0.00, 0.00]));
};