GroupTheory`
GroupTheory`

GTTbFitExport

GTTbFitExport[file,bands] export bands from a tight-binding band structure calculation in GTPack to file to be used to test fitting procedures in SimPack.

Details and Options

  • To test fitting procedures a TB band structure will be exported. Usually the TB parameters are modified by a small noise to simulate a band structure that deviates from the exact TB band structure. Thus, the task of the fit is to find the exact TB parameters.
  • The TB Hamiltonian creates N bands, if N orbitals define the Hamiltonian (N=9 in case of spd-Hamiltonian for Cu). The option GORestrict allows to define the number of bands at each k-point that will be used in the fit.
  • Weight factors might be also defined in the fitting procedure itself.
  • The following options can be used:
  • GOVerbose TrueControls the output of additional information
    GORestrict {}defines selection of bands
  • See: Documentation of SimPack and Tutorial SimPack

Examples

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Basic Examples  (4)

First load the package:

Load the fcc Hamiltonian from file and prepare it for the calculation of the Cu band structure.

Choose the path in Brillouin zone and calculate the band structure.

Set directory for temporary output.

We can customize the band structure for our fitting problem, before the output to a file. We can use: the full band structure, only few lines, or only the symmetry points.

Symmetry points  (1)

Two symmetry lines  (1)

We choose two lines only.

Full band structure  (1)

Options  (2)

GOVerbose  (1)

GORestrict  (1)

In one example above the band structure along two lines is considered. Lets assume that we want to take into account all bands at the symmetry points, but only 6 along the lines.

We find the positions of the symmetry points in the list.