gftool.cpa

Coherent cluster approximation (CPA) to substitutional disorder.

For a high-level interface use solve_root to solve the CPA problem for arbitrary frequencies z. Solutions for fixed occupation occ can be obtained on the imaginary axis only using solve_fxdocc_root.

Fixed occupation on the real axis is currently not support. We recommend obtaining the chemical potential mu for the given occ using solve_fxdocc_root on the imaginary axis, and then run solve_root with the given mu on the real axis. In fact, we expect this to be more stable than fixing the charge on the real axis directly.

API

Functions

gf_cmpt_z(z, self_cpa_z, e_onsite, …)	Green’s function for the components embedded in self_cp_z.
restrict_self_root_eq(self_cpa_z, *args, **kwds)	Wrap self_root_eq to restrict the solutions to self_cpa_z.imag > 0.
self_fxdpnt_eq(self_cpa_z, z, e_onsite, …)	Fixed-point equation f(Σ)=Σ for CPA.
self_root_eq(self_cpa_z, z, e_onsite, …)	Root equation r(Σ)=0 for CPA.
solve_fxdocc_root(iws, e_onsite, …[, …])	Determine the CPA self-energy by solving the root problem for fixed occ.
solve_root(z, e_onsite, concentration, …)	Determine the CPA self-energy by solving the root problem.

Classes

RootFxdocc

CPA solution for the self-energy root-equation for fixed occupation.