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.