BilayerGrapheneGenerator

class sknano.generators.BilayerGrapheneGenerator(*args, autogen=True, finalize=True, **kwargs)

Bases: sknano.generators.GrapheneGenerator, sknano.core.structures.BilayerGraphene

Bilayer graphene structure generator class.

Parameters:

• armchair_edge_length (float, optional) –

  Length of armchair edge in Angstroms

  New in version 0.3.10.

• zigzag_edge_length (float, optional) –

  Length of zigzag edge in Angstroms

  New in version 0.3.10.

• length (float, optional) –

  Length of armchair edge in Angstroms

  Deprecated since version 0.3.10: Use armchair_edge_length instead

• width (float, optional) –

  Width of graphene sheet in Angstroms

  Deprecated since version 0.3.10: Use zigzag_edge_length instead

• edge ({'AC', 'armchair', 'ZZ', 'zigzag'}, optional) –

  ArmChair or ZigZag edge along the length of the sheet.

  Deprecated since version 0.3.10: No longer used!

• basis ({list}, optional) –

  List of strs of element symbols or atomic number of the two atom basis (default: [‘C’, ‘C’])

  New in version 0.3.10.

• element2 (element1,) –

  Element symbol or atomic number of basis Atom 1 and 2

  Deprecated since version 0.3.10: Use basis instead

• bond (float, optional) – bond length between nearest-neighbor atoms in Angstroms.
• layer_spacing (float, optional) – Distance between layers in Angstroms.
• stacking_order ({'AA', 'AB'}, optional) – Stacking order of graphene layers
• layer_rotation_angle ({None, float}, optional) – Rotation angle of second layer specified in degrees. If specified in degrees, then you must set degrees=True
• degrees (bool, optional) – The layer_rotation_angle is specified in degrees and needs to be converted to radians.
• autogen (bool, optional) – if True, automatically generate unit cell and full structure
• verbose (bool, optional) – verbose output

Examples

Import the BilayerGrapheneGenerator class

>>>

>>> from sknano.generators import BilayerGrapheneGenerator

Generate 100 Å wide by 10 Å long AB stacked bilayer-graphene:

>>>

>>> bilayer_graphene = BilayerGrapheneGenerator(armchair_edge_length=100,
...                                             zigzag_edge_length=10)

Save structure data in xyz format:

>>>

>>> bilayer_graphene.save()

Here’s the rendered structure (after rotating 90 degrees so that it better fits the page):

The next command generates bilayer-graphene with its second layer rotated 45 degrees.

>>>

>>> rotated_bilayer =     ...     BilayerGrapheneGenerator(armchair_edge_length=50,
...                              zigzag_edge_length=50,
...                              layer_rotation_angles=[0, 45],
...                              degrees=True)
>>> rotated_bilayer.save(fname='rotated_bilayer.xyz')

A rendering of rotated_bilayer:

The next example is identical to the one above, except the atomic basis is Boron and Nitrogen.

>>>

>>> rotated_BN_bilayer =     ...     BilayerGrapheneGenerator(armchair_edge_length=50,
...                              zigzag_edge_length=50,
...                              basis=['B', 'N'],
...                              layer_rotation_angles=[0, 45],
...                              degrees=True)
>>> rotated_BN_bilayer.save(fname='rotated_bilayer_B-N_basis.xyz')

The rendered structure looks like:

Attributes

N	Number of graphene unit cells.
Natoms	N atoms.
Natoms_per_layer	Number of atoms per layer.
Natoms_per_unit_cell	Number of atoms per unit cell.
area	Total area of graphene supercell.
atoms	Structure Atoms.
basis	NanoStructureBase basis objects.
crystal_cell	Structure CrystalCell.
element1	Basis element 1
element2	Basis element 2
fmtstr	Format string.
lattice	Structure Crystal3DLattice.
lattice_shift	Lattice displacement vector.
mass	Total mass of atoms.
n1	Number of unit cells along Crystal3DLattice.a1.
n2	Number of unit cells along Crystal3DLattice.a2.
r1	Vector GrapheneMixin.n1 $\times$ Crystal3DLattice.a1.
r2	Vector GrapheneMixin.n2 $\times$ Crystal3DLattice.a2.
scaling_matrix	CrystalCell.scaling_matrix.
structure	An alias to self.
unit_cell	Structure UnitCell.
vdw_distance	Van der Waals distance.
vdw_radius	Van der Waals radius

Methods

clear()	Clear list of StructureMixin.atoms.
finalize()	Finalize structure data by assigning unique ids and types to structure atoms.
from_conventional_cell(**kwargs)	classmethod
from_primitive_cell(**kwargs)	classmethod
generate([finalize])	Generate the full structure coordinates.
generate_fname([armchair_edge_length, ...])	Generate a filename string.
make_supercell(scaling_matrix[, wrap_coords])	Make supercell.
rotate(**kwargs)	Rotate crystal cell lattice, basis, and unit cell.
save([fname])	Save structure data.
todict()	Return dict of constructor parameters.
transform_lattice(scaling_matrix[, ...])	Transform structure lattice.
translate(t[, fix_anchor_points])	Translate crystal cell lattice, basis, and unit cell.
write(*args, **kwargs)	Write structure data to file.
write_data(**kwargs)	Write LAMMPS data file.
write_dump(**kwargs)	Write LAMMPS dump file.
write_pdb(**kwargs)	Write pdb file.
write_xyz(**kwargs)	Write xyz file.