Structure-Dependent Electronic and Optical Properties of theMartensitic Alloys TiAu

The atomic and electronic structures together with the optical properties of TiAu in the low-temperature B19 and B11 phases are calculated by using first principles local density functional approaches. Our results show that the B11 structure is more stable than B19 for TiAu alloy in ordered equiatomic composition (Ti : Au = 50 : 50). In low temperature, the B11 structure should exist as a binary alloy from the energetic consideration. The accurate atomic positions in the unit cell have been given by fully force relaxed calculations. The calculated optical conductivities of B19 and B11 phases show drastic change in the region of 1.5 to 3.5eV.