Self-Consistent Cluster Theory for Electronic Structure of Systems with Local Orders. II. Application to Amorphous Si

Abstract

Electronic density of states of amorphous Si is investigated with the use of the self-consistent cluster theory developed in the preceding paper. E-k relations and local densities of states are calculated for 1-, 2- and 8-atom cluster cases. Effect of local orders is elucidated by comparing the results in these three cases. Density of states with pseudogap at the Fermi energy is obtained for 8-atom cluster case, in which the two central atoms are in the tetrahedral environment. By using the sp³ hybridized orbitals the structure in state density is analyzed and the origin of the pseudogap is clarified to be the bonding-anti-bonding splitting of the hybridized orbitals.