The following script file provides an initial structure for GeH monolayer, which is constructed by removing Ga atoms and Ge atoms in the crystal structure of beta-CaGe2 and by adding hydrogen atoms.
# Set up lattice
lattice = Hexagonal(3.9872*Angstrom, 30.583*Angstrom)
# Define elements
elements = [Germanium, Germanium, Hydrogen, Hydrogen]
# Define coordinates
fractional_coordinates = [[ 0.66666667, 0.33333333, 0.51798333],
[ 0.33333333, 0.66666667, 0.48201667],
[ 0.60134218, 0.28773871, 0.56743569],
[ 0.28773871, 0.60134218, 0.43256431]]
# Set up configuration
bulk_configuration = BulkConfiguration(
bravais_lattice=lattice,
elements=elements,
fractional_coordinates=fractional_coordinates
)
To a proper structure of monolayer GeH, one must optimize this initial structure for the in-plane lattice constant and atomic coordinates.