Common geometries (sisl.geom
)¶
A variety of default geometries.
Basic¶
-
sisl.geom.
sc
(alat, atom) Simple cubic lattice with 1 atom
-
sisl.geom.
bcc
(alat, atoms, orthogonal=False) Body centered cubic lattice with 1 (non-orthogonal) or 2 atoms (orthogonal)
-
sisl.geom.
fcc
(alat, atoms, orthogonal=False) Face centered cubic lattice with 1 (non-orthogonal) or 4 atoms (orthogonal)
-
sisl.geom.
hcp
(a, atoms, coa=1.63333, orthogonal=False) Hexagonal closed packed lattice with 2 (non-orthogonal) or 4 atoms (orthogonal)
1D materials¶
-
sisl.geom.
nanoribbon
(bond, atoms, width, kind='armchair') Construction of a nanoribbon unit cell of type armchair or zigzag.
The geometry is oriented along the \(x\) axis.
- Parameters
See also
honeycomb
honeycomb lattices
graphene
graphene geometry
graphene_nanoribbon
graphene nanoribbon
agnr
armchair graphene nanoribbon
zgnr
zigzag graphene nanoribbon
-
sisl.geom.
graphene_nanoribbon
(width, bond=1.42, atoms=None, kind='armchair') Construction of a graphene nanoribbon
- Parameters
See also
honeycomb
honeycomb lattices
graphene
graphene geometry
nanoribbon
honeycomb nanoribbon (used for this method)
agnr
armchair graphene nanoribbon
zgnr
zigzag graphene nanoribbon
-
sisl.geom.
agnr
(width, bond=1.42, atoms=None) Construction of an armchair graphene nanoribbon
- Parameters
See also
honeycomb
honeycomb lattices
graphene
graphene geometry
nanoribbon
honeycomb nanoribbon
graphene_nanoribbon
graphene nanoribbon
zgnr
zigzag graphene nanoribbon
-
sisl.geom.
zgnr
(width, bond=1.42, atoms=None) Construction of a zigzag graphene nanoribbon
- Parameters
See also
honeycomb
honeycomb lattices
graphene
graphene geometry
nanoribbon
honeycomb nanoribbon
graphene_nanoribbon
graphene nanoribbon
agnr
armchair graphene nanoribbon
-
sisl.geom.
nanotube
(bond, atoms=None, chirality=1, 1) Nanotube with user-defined chirality.
This routine is implemented as in ASE with some cosmetic changes.
2D materials¶
-
sisl.geom.
honeycomb
(bond, atoms, orthogonal=False) Honeycomb lattice with 2 or 4 atoms per unit-cell, latter orthogonal cell
This enables creating BN lattices with ease, or graphene lattices.
- Parameters
See also
graphene
the equivalent of this, but with default of Carbon atoms
bilayer
create bilayer honeycomb lattices
-
sisl.geom.
graphene
(bond=1.42, atoms=None, orthogonal=False)[source] Graphene lattice with 2 or 4 atoms per unit-cell, latter orthogonal cell
-
sisl.geom.
bilayer
(bond=1.42, bottom_atoms=None, top_atoms=None, stacking='AB', twist=0, 0, separation=3.35, ret_angle=False, layer='both') Commensurate unit cell of a hexagonal bilayer structure, possibly with a twist angle.
This routine follows the prescription of twisted bilayer graphene found in 1.
Notes
This routine may change in the future to force some of the arguments.
- Parameters
bond (float, optional) – bond length between atoms in the honeycomb lattice
bottom_atoms (Atom, optional) – atom (or atoms) in the bottom layer. Defaults to
Atom(6)
top_atoms (Atom, optional) – atom (or atoms) in the top layer, defaults to bottom_atom
stacking ({'AB', 'AA', 'BA'}) – stacking sequence of the bilayer, where XY means that site X in bottom layer coincides with site Y in top layer
twist (tuple of int, optional) – integer coordinates (m, n) defining a commensurate twist angle
separation (float, optional) – distance between the two layers
ret_angle (bool, optional) – return the twist angle (in degrees) in addition to the geometry instance
layer ({'both', 'bottom', 'top'}) – control which layer(s) to return
See also
honeycomb
honeycomb lattices
graphene
graphene geometry
References
- 1
Trambly de Laissardiere, D. Mayou, L. Magaud, “Localization of Dirac Electrons in Rotated Graphene Bilayers”, Nano Letts. 10, 804-808 (2010)