gftool.matrix.gf_2x2_z
- gftool.matrix.gf_2x2_z(z, eps0, eps1, hopping, hilbert_trafo=None)[source]
Calculate the diagonal Green’s function elements for a 2x2 system.
- Parameters:
- z(…) complex array_like
Complex frequencies.
- eps0, eps1(…) float or complex array_like
On-site energy of element 0 and 1. For interacting systems this can be replaced by on-site energy + self-energy.
- hopping(…) float or complex array_like
Hopping element between element 0 and 1.
- hilbert_trafoCallable, optional
Hilbert transformation. If given, return the local Green’s function. Else the lattice dispersion \(ϵ_k\) can be given via z → z - ϵ_k.
- Returns:
- (…, 2) complex array_like
Diagonal elements of the Green’s function of the 2x2 system.
Notes
For the trivial case eps0==eps1 and hopping==0, this implementation fails.