class sknano.generators.UnrolledSWNTGenerator(*args, *, autogen=True, **kwargs)[source][source]

Class for generating unrolled nanotube structures.

New in version 0.2.23.


n, m : int

Chiral indices defining the nanotube chiral vector \(\mathbf{C}_{h} = n\mathbf{a}_{1} + m\mathbf{a}_{2} = (n, m)\).

nx, ny, nz : int, optional

Number of repeat unit cells in the \(x, y, z\) dimensions

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.

element1, element2 : {str, int}, optional

Element symbol or atomic number of basis Atom 1 and 2

Deprecated since version 0.3.10: Use basis instead

bond : float, optional

\(\mathrm{a}_{\mathrm{CC}} =\) distance between nearest neighbor atoms. Must be in units of Angstroms.

Lx, Ly, Lz : float, optional

Length of bundle in \(x, y, z\) dimensions in nanometers. Overrides the \(n_x, n_y, n_z\) cell values.

fix_Lz : bool, optional

Generate the nanotube with length as close to the specified \(L_z\) as possible. If True, then non integer \(n_z\) cells are permitted.

autogen : bool, optional

if True, automatically call generate.

verbose : bool, optional

if True, show verbose output


The UnrolledSWNTGenerator class generates graphene using the nanotube unit cell defined by the chiral vector \(\mathbf{C}_{h} = n\mathbf{a}_{1} + m\mathbf{a}_{2} = (n, m)\). If you want to generate graphene with an armchair or zigzag edge using length and width parameters, see the GrapheneGenerator class.


First, load the UnrolledSWNTGenerator class.

>>> from sknano.generators import UnrolledSWNTGenerator

Now let’s generate an unrolled \(\mathbf{C}_{\mathrm{h}} = (10, 5)\) SWCNT unit cell.

>>> flatswcnt = UnrolledSWNTGenerator(10, 5)

The rendered structure looks like:


Ch SWNT circumference \(|\mathbf{C}_h|\) in
Ch_vec SWNT chiral vector.
Lz SWNT length \(L_z = L_{\mathrm{tube}}\) in nanometers.
M \(M = np - nq\)
N Number of graphene hexagons in nanotube unit cell.
Natoms Number of atoms in nanotube.
Natoms_per_tube Number of atoms in nanotube \(N_{\mathrm{atoms/tube}}\).
Natoms_per_unit_cell Number of atoms in nanotube unit cell.
Ntubes Number of nanotubes.
R Symmetry vector \(\mathbf{R} = (p, q)\).
T Length of nanotube unit cell \(|\mathbf{T}|\) in Å.
Tvec SWNT translation vector.
atoms Structure StructureAtoms.
basis NanoStructureBase basis atoms.
chiral_angle Chiral angle \(\theta_c\) in degrees.
chiral_type SWNT chiral type.
crystal_cell Structure CrystalCell.
d \(d=\gcd{(n, m)}\)
dR \(d_R=\gcd{(2n + m, 2m + n)}\)
dt Nanotube diameter \(d_t = \frac{|\mathbf{C}_h|}{\pi}\) in Å.
electronic_type SWNT electronic type.
element1 Basis element 1
element2 Basis element 2
fmtstr Format string.
lattice Structure Crystal3DLattice.
linear_mass_density Linear mass density of nanotube in g/nm.
m Chiral index \(m\).
n Chiral index \(n\).
nlayers Number of layers.
nx Number of unit cells along the \(x\)-axis.
nz Number of nanotube unit cells along the \(z\)-axis.
rt Nanotube radius \(r_t = \frac{|\mathbf{C}_h|}{2\pi}\) in Å.
scaling_matrix CrystalCell.scaling_matrix.
structure Pointer to self.
structure_data Alias for BaseStructureMixin.structure.
t1 \(t_{1} = \frac{2m + n}{d_{R}}\)
t2 \(t_2 = -\frac{2n + m}{d_R}\)
tube_length Alias for SWNT.Lz
tube_mass SWNT mass in grams.
unit_cell Structure UnitCell.
unit_cell_mass Unit cell mass in atomic mass units.
unit_cell_symmetry_params Tuple of SWNT unit cell symmetry parameters.
vdw_distance van der Waals distance.
vdw_radius van der Waals radius


clear() Clear list of BaseStructureMixin.atoms.
generate() Generate structure data.
generate_fname([n, m, nx, nz, fix_Lx, fix_Lz])
generate_unit_cell() Generate the nanotube unit cell.
make_supercell(scaling_matrix[, wrap_coords]) Make supercell.
read_data(*args, **kwargs)
read_dump(*args, **kwargs)
read_xyz(*args, **kwargs)
rotate(**kwargs) Rotate crystal cell lattice, basis, and unit cell.
save([fname, outpath, structure_format, ...]) Save structure data.
todict() Return dict of SWNT attributes.
transform_lattice(scaling_matrix[, ...])
translate(t[, fix_anchor_points]) Translate crystal cell basis.