Parallel lanczos algorithm on a CRAY-T3D combining PVM and SHMEM routines

摘要

The metal insulator transition (MIT) of cubic tungsten bronzes Na spb x WO sub 3 has been studied in detail as a function of composition x and temperature [6]. One theoretical approach to address the question of the origin of the MIT in the Na sub x WO sub 3 bronzes incorporating electron interaction and correlated disorder is a two-dimensional Anderson-Mott-Hubbard (AMH) model [7]. The resulting Hamiltonian matrix H has to be solved in an unrestricted Hartree-Fock (UHF) approach, t.m. independently for electrons in teh two spin states alhha and beta. At each step of an UHF iteration the matrix H has to be diagonalized. Only conduction band (CB) states are taken into account, t.m. approximately 3