ELECTRONIC-STRUCTURE AND BONDING PROPERTIES OF TITANIUM SILICIDES

We present an ab initio full-potential linear muffin-tin orbital study of the structural and electronic properties of seven compounds of the binary Ti-Si system. The calculations were done with the compounds in their proposed stable structures, which are A3 Ti, D8(8) Ti5Si3, B27 TiSi, TiSi in distorted L1(0), C49 TiSi2, C54 TiSi2, and A4 Si. The ca lculated enthalpies of formation reproduce the observed sequence of st able structures and agree reasonably well with the values deduced from experiments. The paper ends with an analysis of the electronic struct ure and the bonding in the stable phases, which shows that the propert ies of the experimentally observed stable phases differ considerably f rom those of the hypothetical unstable structures. Therefore, the latt er represent a poor model for the bonding in some of the stable Ti-Si compounds. We suggest that the bonding in these structures has a compl ex character extending beyond simple Ti-Ti and Ti-Si pairwise interact ions. [S0163-1829(98)06707-1].