Study of the electronic local density of states using the cluster-Bethe-lattice method: Application to amorphous III-V semiconductors

The cluster-Bethe-lattice method is extended to study the Weaire-Thorpe $s{p}^3$ Hamiltonian. We derive a transformation which makes it possible to calculate the local density of states of a system described with a four-orbital Hamiltonian by using the local Green's function of a one-orbital Hamiltonian. We study the effects on the density of states of the presence of like-atom bonds in amorphous III-V semiconductors. We analyze two models: (a) like-atom bond in tetrahedral configuration, and (b) like-atom bond in triangular pyramidal configuration. Our results are in agreement with the experimental data.