kwant.physics.Bands

class kwant.physics.Bands(sys, args=(), *, params=None)

Class of callable objects for the computation of energy bands.

Parameters

syskwant.system.InfiniteSystem

The low level infinite system for which the energies are to be calculated.

argstuple, defaults to empty

Positional arguments to pass to the hamiltonian method. Deprecated in favor or ‘params’ (and mutually exclusive with it).

paramsdict, optional

Dictionary of parameter names and their values. Mutually exclusive with ‘args’.

Notes

An instance of this class can be called like a function. Given a momentum (currently this must be a scalar as all infinite systems are quasi-1-d), it returns a NumPy array containing the eigenenergies of all modes at this momentum. If derivative_order > 0 or return_eigenvectors = True, additional arrays are returned.

Examples

>>> bands = kwant.physics.Bands(some_syst)
>>> momenta = numpy.linspace(-numpy.pi, numpy.pi, 101)
>>> energies = [bands(k) for k in momenta]
>>> pyplot.plot(momenta, energies)
>>> pyplot.show()

Methods