Novel stable hard transparent conductors in TiO(2)-TiC system: Design materials from scratch

Two new ternary compounds in the TiO(2)-TiC system, Ti(5)C(2)O(6) and Ti(3)C(2)O(2), are reported for the first time based on ab initio evolutionary algorithm. Ti(5)C(2)O(6) has a tube-structure in which sp(1) hybridized carbon chains run through the lattice along the b-axis; while in the Ti(3)C(2)O(2) lattice, double TiO(6) polyhedral are separated by the non-coplanar sp(2) hybridized hexagon graphite layers along the c-axis, forming a sandwich-like structure. At ambient conditions, the two compounds are found to be mechanically and dynamically stable and intrinsic transparent conductors with high hardness (about twice harder than the conventional transparent conducting oxides). These mechanical, electronic, and optical properties make Ti(5)C(2)O(6) and Ti(3)C(2)O(2 )ternary compounds be promising robust, hard, transparent, and conductive materials.