Random-bethe-lattice model applied to the electronic structure of amorphous and liquid silicon

TLDR: A unified picture of the electronic structure of Si in amorphous and liquid phases is obtained through a well-grounded extension of the coherent-potential approximation to random Bethe lattices with off-diagonal disorder.

Abstract: Bethe lattices of arbitrary number of nearest-neighbor atoms and geometrical configurations are defined for the standard {ital sp}{sup 3}{ital s*} tight-binding Hamiltonian that gives correctly both valence and conduction bands of crystalline Si. Averaged densities of states are obtained through a well-grounded extension of the coherent-potential approximation to random Bethe lattices with off-diagonal disorder. In that way, a unified picture of the electronic structure of Si in amorphous and liquid phases is obtained. Formation energies of dangling and floating bonds are estimated within Chadi's tight-binding scheme.