Electronic structure of the layered ternary carbides Ti2SnC and Ti2GeC

The electronic structure of the layered ternary carbides Ti2SnC and Ti2GeC has been investigated by means of ab initio linear combination of atomic or bital calculations. The calculated band structure shows that the electrical conductivity for both Ti2SnC and Ti2GeC is metallic and anisotropic with a high density of states at the Fermi level. The electrical conductivity of Ti2SnC is, however, higher than that of Ti2GeC. The major factors governing the electronic properties are pd hybridization from Ti 3d and C 2p states. Compared to the structure of TiC, the presence of Sn or Ge changes the Ti- C-Ti-C covalent bond chain into a Ti-C-Ti-Sn or Ti-C-Ti-Ge bond chain throu gh its reaction with Ti, forming the layered structure.