Comparison of density of states of transition metal disilicides and their related compounds systematically calculated by a first-principle pseudopotential method using plane-wave basis

Density of states of transition metal disilicides and their related compounds of the following types of structures have been calculated by a first-principle pseudopotential method using plane-wave basis, CASTEP; CaF2, alpha- and beta-FeSi2, TiSi2, ZrSi2, CrSi2, MoSi2, Mn4Si7, Ru2Si3, and AlB2. The principle of "DOS at Fermi level would be hopefully smaller in energetically-favored structure" is valid in most of silicides except for IIIa elements. The broadening of the energy difference between the bonding and anti-bonding states by promotion to the heavier element in the same group in periodic table is dependent on the crystal structure and this may cause the transition of the structure in the same group. Semiconducting property of ReSi2 is probably due to the vacancies located at silicon sites because DOS at Fermi level has relatively large value for stoichiometric ReSi2. Also, it is pointed out that the formula of Mn11Si19 is not consistent with the intrinsic semiconducting nature. (C) 2000 Elsevier Science Ltd. All rights reserved.