Chimie Théorique » QMX

"""Function-like objects creating lattices with more than one element.

These lattice creators are mainly intended as examples for how to build you

own.  The following crystal structures are defined:

    B1 = NaCl = Rocksalt

    B2 = CsCl

    B3 = ZnS = Zincblende

    L1_2 = AuCu3

    L1_0 = AuCu

"""

from ase.lattice.cubic import FaceCenteredCubicFactory,\

    BodyCenteredCubicFactory, DiamondFactory, SimpleCubicFactory

from ase.lattice.tetragonal import SimpleTetragonalFactory

import numpy as np

from ase.data import reference_states as _refstate

# To prevent a layer of element one on one side, and a layer of

# element two on the other side, NaCl is based on SimpleCubic instead

# of on FaceCenteredCubic

class NaClFactory(SimpleCubicFactory):

    "A factory for creating NaCl (B1, Rocksalt) lattices."

    bravais_basis = [[0, 0, 0], [0, 0, 0.5], [0, 0.5, 0], [0, 0.5, 0.5],

                     [0.5, 0, 0], [0.5, 0, 0.5], [0.5, 0.5, 0],

                     [0.5, 0.5, 0.5]]

    element_basis = (0, 1, 1, 0, 1, 0, 0, 1)

B1 = NaCl = Rocksalt = NaClFactory()

class CsClFactory(SimpleCubicFactory):

    "A factory for creating CsCl (B2) lattices."

    bravais_basis = [[0, 0, 0], [0.5, 0.5, 0.5]]

    element_basis = (0, 1)

B2 = CsCl = CsClFactory()

#The zincblende structure is easily derived from Diamond, which

#already has the right basis.

class ZnSFactory(DiamondFactory):

    "A factory for creating ZnS (B3, Zincblende) lattices."

    element_basis = (0, 1)

B3 = ZnS = Zincblende = ZnSFactory()

# The L1_0 structure is "based on FCC", but is a tetragonal distortion

# of fcc.  It must therefore be derived from the base-centered

# tetragonal structure.  That structure, however, does not exist,

# since it is equivalent to a simple tetragonal structure rotated 45

# degrees along the z-axis.  Basing L1_2 on that would however give

# unexpected miller indices.  L1_2 will therefore be based on a simple

# tetragonal structure, but with a basis corresponding to a

# base-centered tetragonal.

class AuCuFactory(SimpleTetragonalFactory):

    "A factory for creating AuCu (L1_0) lattices (tetragonal symmetry)."

    bravais_basis = [[0, 0, 0], [0, 0.5, 0.5], [0.5, 0, 0.5], [0.5, 0.5, 0]]

    element_basis = (0, 1, 1, 0)

AuCu = L1_0 = AuCuFactory()

# The L1_2 structure is "based on FCC", but is really simple cubic

# with a basis.

class AuCu3Factory(SimpleCubicFactory):

    "A factory for creating AuCu3 (L1_2) lattices."

    bravais_basis = [[0, 0, 0], [0, 0.5, 0.5], [0.5, 0, 0.5], [0.5, 0.5, 0]]

    element_basis = (0, 1, 1, 1)

AuCu3 = L1_2 = AuCu3Factory()