Abstract: The densities of electronic states (DOS) of quasi-one-dimensional disordered systems with three parallel chains are computed with thirty thousand sites based on the negative eigenvalue theory. Compared with one-dimensional and quasi-one-dimensional disordered systems under conditions as diagonal disordered system and non-diagonal disordered system, the electronic structure, the localization of electrons, the distribution of the system energy and the dimensional effects are discussed. The results show that the diagonal disorder causes increasing of the number of localized electrons, and the non-diagonal disorder leads to changing of the distribution of the system energy. Comparing the electronic structure of one-dimensional system and quasi-one-dimensional system with three chains, we find that the peak number of the DOS increase, and the bandgap energy of zero DOS decreases.The dimensional effect of system under the same condition is shown.

Key words: quasi-one-dimensional three parallel chains, disordered system, electronic structure