radtools.SpinHamiltonian.add_bond

method

SpinHamiltonian.add_bond(atom1: Atom, atom2: Atom, R, J: ExchangeParameter = None, **kwargs)

Add one bond to the Hamiltonian.

More straightforward syntax is advised:

>>> import radtools as rad
>>> Cr = rad.Atom("Cr")
>>> J = rad.ExchangeParameter(iso=1)
>>> model = rad.SpinHamiltonian(rad.Crystal())
>>> model[Cr, Cr, (1,0,0)] = J
>>> (Cr, Cr, (1,0,0)) in model
True

It is equivalent to

>>> import radtools as rad
>>> Cr = rad.Atom("Cr")
>>> J = rad.ExchangeParameter(iso=1)
>>> model = rad.SpinHamiltonian(rad.Crystal())
>>> model.add_bond(Cr, Cr, (1,0,0), J=J)
>>> (Cr, Cr, (1,0,0)) in model
True

Parameters:

atom1Atom or str

Atom object in (0, 0, 0) unit cell. str works only if atom is already in the Hamiltonian.

atom2Atom or str

Atom object in R unit cell. str works only if atom is already in the Hamiltonian.

Rtuple of ints

Vector of the unit cell for atom2. In the relative coordinates (i,j,k).

JExchangeParameter, optional

An instance of ExchangeParameter.

** kwargs

Keyword arguments for the constructor of ExchangeParameter. Ignored if J is given.