A Davidson-Lanczos iteration method for computation of   continued-fraction expansion of the Green's function at very low   temperatures: Applications to the dynamical mean field theory
  We present a combination method based on orignal version of Davidson algorithm for extracting few of the lowest eigenvalues and eigenvectors of a sparse symmetric Hamiltonian matrix and the simplest version of Lanczos technique for obtaining a tridiagonal representation of the Hamiltonian to compute the continued fraction expansion of the Green's function at a very low temperature. We compare the Davidson$+$Lanczos method with the full diagonalization on a one-band Hubbard model on a Bethe lattice of infinite-coordination using dynamical mean field theory. 
Medha Sharma and M.A.H. Ahsan
cond-mat.str-el