Convenience Parameter Setting

elecboltz.easy_params(params)

Convenience function to set parameters for the simulation.

List of convenience features:

• Load parameters from the output of a fit from the path indicated

  by the load_fit parameter.
• Set unit cell dimensions with named parameters a, b,

  and c. If b or c are not given, they are assumed

  to be equal to a.

• Define an energy_scale which scales all energy parameters.

• Set the chemical potential with mu in band_params. If

  mu is set in band_params, it is assumed the energy

  dispersion is shifted by the chemical potential, so the

  associated variable is set to 0.0 in the returned parameters.
• Set the dispersion relation with a default tight-binding model;

  If dispersion is not given, it is automatically generated

  from the band_params using get_tight_binding_dispersion.

  See get_tight_binding_dispersion for the list of parameters

  and the resulting expression.
• Build the scattering function using predefined

  scattering_models and the scattering_params associated

  with them. See build_scattering_function() for supported

  scattering models and their parameters. scattering_models

  is assumed to be only one isotropic model if not specified.
• Build the scattering kernel using a predefined

  scattering_kernel (or a list of scattering_kernels) and

  the kernel_params associated with it (or a list of

  kernel_params associated with each kernel). See

  build_kernel() for supported kernels and their parameters.

Parameters:

params (dict) – Simplified (easy-to-use) parameters for the simulation.

Returns:

Parameters compatible with the classes in the package.

Return type:

dict

elecboltz.params.get_tight_binding_dispersion(band_params) → str

Get the tight-binding dispersion relation containing terms relating to the parameters in band_params.

The full tight-binding dispersion relation is given by:

-mu - 2*t * (cos(a*kx)+cos(b*ky))
- 4*tp * cos(a*kx)*cos(b*ky)
- 2*tpp * (cos(2*a*kx)+cos(2*b*ky))
- 2*tz * (cos(a*kx)-cos(b*ky))**2
    * cos(a*kx/2)*cos(b*ky/2)*cos(c*kz/2)

The list of parameters is as follows:

• mu: Chemical potential.

• t: Nearest-neighbor hopping parameter in the x-y plane.

• tp: Next-nearest-neighbor hopping parameter in the x-y plane.

• tpp: Next-next-nearest-neighbor hopping parameter in the x-y plane.

• tz: Nearest-neighbor hopping parameter between the different layers in the z direction.

Parameters:

band_params (dict or set) – Dictionary or set of parameters for the tight-binding model.

Returns:

The dispersion relation expression string

Return type:

str