GroupTheory`
GroupTheory`

GTTbToFortran

GTTbToFortran[Hamiltonian,maximal angular momentum,maximum shell number,file name]

transforms a k-space tight-binding Hamiltonian into a FORTRAN module.

Details and Options

  • GTPack constructs Hamiltonians in an analytic form. Numerical calculations (band structure, density of states) can also be performed. Sometimes it is more efficient to do numerical calculations outside of Mathematica. GTTbToFortran translates the Hamiltonian into a FORTRAN module for further use in other program packages.
  • If a parameter set corresponding to the constructed Hamiltonian is available, this set can substitute maximal angular momentum in the input. The list of symbols will be extracted from the parameter set.
  • The command saves time in programming, but the result has to be checked carefully!
  • The following options can be given:
  • GOTbBasis 0Suppresses subscripts within element names
    GOVerbose FalseControls the output of additional information
  • See: W. Hergert, M. Geilhufe, Group Theory in Solid State Physics and Photonics. Problem Solving with Mathematica

Examples

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Basic Examples  (1)

First load the package:

Set the directory of pre-defined data

Read the Hamiltonian for fcc structure and spd basis

The maximum angular momentum is l=2 and the maximum shell number is sh=2.

Instead of a maximum angular momentum an external parameter set can be used. The parameters are extracted from this parameter set and are not generated internally.

Options  (2)

GOVerbose  (1)

The FORTRAN code is not displayed.

The Hamiltonian transformed to FORTRAN is printed out.

GOTbBasis  (1)

The Hamiltonian for zinc blende structure is read.

The Hamiltonian contains s and p orbitals but also a s* orbital. Instead of the definition of a maximum l, a parameter set from a database is used.

GTTbParameterNames extracts the parameter symbols from a parameter set. This method is used in GTTbToFortran .