GROUP THEORY SYMBOL

GOTbLattice

GOTbLattice
is an option to provide detailed information for the construction of tight-binding Hamiltonians from the shell construction, if more than one atom is present in the basis.

DetailsDetails

  • The option has to provide information about the interactions which will be taken into account in the construction of the Hamiltonian. It is given as a list of the structure:
  • {interaction1,interaction2,...}
  • consisting of sublists of the form:
  • {"atom1,atom2",{shell1,shell2,...}}
  • If equivalent atoms appear in the basis GOTbEquivalence has to be set to False in the cluster construction with GTCluster.
  • The procedure to consider equivalent atoms in the basis as inequivalent and to construct rules to make them equivalent in the final Hamiltonian again is necessary to construct the Hamiltonian first and to keep the tight-binding parameter sets small, i.e. in BaTiO3 is only one "Ba,O" interaction and not three different ones ("Ba,O1","Ba,O2","Ba,O3").
  • This option is used by: GTShells

ExamplesExamplesopen allclose all

Basic Examples  (1)Basic Examples  (1)

First load the package:

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Install crystall structures

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GaAs

GaAs crystallizes in the zinc blende structure.

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Customize for GaAs

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Construct the cluster

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Information about basis and shells

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Construction of the shells

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Only the nearest neighbor interaction between Ga and As is taken into account. Interactions between the Ga atoms and interactions between the As atoms are switched off, i.e. in the Hamiltonian the Ga-Ga and As-As blocks contain only on-site energies.

BaTiO_3

Load the structure for BTO

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BTO contains three eqivalent O atoms. They will be set inequivalent for the cluster construction.

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Information about the basis and shells

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Three shells will be considered for each basis atom.

The final goal is the construction of a Hamiltonian for BTO containing only the interactions of Ti and O atoms.

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A direct interaction Ti-Ti and O-O is not taken into account. The nearest neighbor Ti-O interaction and the nearest neighbor O-O interaction is taken into account. (cf. table O-O nearest O-O interaction is second shell !)