unitcell — A unitcell definition.
unitcell ::= (parameter*)
The unitcell element describes the supercell for condensed matter systems.
Initialize the geometrical parameters of a unit cell.
The following elements occur in simulation: parameter
Optional, the Dimension of a unitcell. Default is 3.
Optional, ID type.
Optional, the unit of the lattice vectors.
Reserved.
The list of parameters meaningful to unitcell. The attribute datatype is implied and is set by an application and the dimension D, the value dimension attribute of unitcell.
| name | condition | datatype | result |
|---|---|---|---|
| scale | AA | bohr | scalar | Set a scaling factor of a unit cell. AA(bohr) is the length unit in Angstrom (bohr). Default is 1 AA. |
| lattice | AA | bohr | tensor | Set lattice vectors by a D-by-D tensor |
| bconds | none | char | Set the boundary conditions in the D directions. Default is p p p for periodic boundary condition. n is used to indicate that a direction is not periodic. |
| grid | none | integer | Set the grid partition in the D directions |
| mpi_grid | none | integer | Set the mpi grid partition in the D directions |
| omp_grid | none | integer | Set the openmp grid partition in the D directions |
A cubic unit cell with the lattice parameter 5.432 A is written as
<unitcell dimension="3">
<parameter name="scale" condition="AA">5.432 </parameter>
<parameter name="lattice" datatype="tensor">
1.0 0.0 0.0
0.0 1.0 0.0
0.0 0.0 1.0
</parameter>
<parameter name="bconds" datatype="char"> p p p </parameter>
</unitcell>