Cracks

To create a v-shaped defect in a material, the Notch geometry can be used. In this example we create a slab of \(\alpha\)-quartz and carve out a crack made with the Notch geometry.

First, we import the necessary packages:

from molecular_builder.core import create_bulk_crystal, write, carve_geometry
from molecular_builder.geometry import NotchGeometry
import ase.cell 

Then, we create our slab of \(\alpha\)-quartz. We use block dimensions of (100Å, 50Å, 100Å)

L = [100,50,100]

quartz_structure = create_bulk_crystal("alpha_quartz", L) 
cell = quartz_structure.get_cell(); cell[0,1] = 0; cell[1,0] = 0; cell[0,2] = 0; cell[2,0] = 0; cell[1,2] = 0; cell[2,1] = 0
quartz_structure.set_cell(cell); quartz_structure.wrap()

The code below will create and carve out a crack in the \(\alpha\)-quartz using the Notch geometry:

crack = NotchGeometry([0,L[1]/2,L[2]/2], [20,0,0], [0,0,10])
carve_geometry(quartz_structure, crack, side="in")

The resulting system looks like this:

An crack in a slab of \(\alpha\)-quartz.

Full code of this example:

from molecular_builder.core import create_bulk_crystal, write, carve_geometry
from molecular_builder.geometry import NotchGeometry
import ase.cell 

L = [100,50,100]

quartz_structure = create_bulk_crystal("alpha_quartz", L) 
cell = quartz_structure.get_cell(); cell[0,1] = 0; cell[1,0] = 0; cell[0,2] = 0; cell[2,0] = 0; cell[1,2] = 0; cell[2,1] = 0
quartz_structure.set_cell(cell); quartz_structure.wrap()

crack = NotchGeometry([0,L[1]/2,L[2]/2], [20,0,0], [0,0,10])
carve_geometry(quartz_structure, crack, side="in")

write(quartz_structure, "alpha_quartz_with_crack.png",  camera_dir=[0, 1, 0], viewport_type="perspective")