Structural, Electronic and Optical Properties of Cubic CaCu3Ti4–xAgxO12 Perovskite Ceramics: A First-Principles Study

The Structural, electronic and optical properties of cubic CaCu
₃
Ti
_4-x
Ag
_x
O
₁₂
(x = 0, 0.5, 1, 1.5 and 2) perovskite ceramics have been investigated by the first principle method. The CaCu
₃
Ti
_4-x
Ag
_x
O
₁₂
ceramics still maintains the bcc lattice and the lattice constants increase with the increasing Ag concentration. The formation energies of the CaCu
₃
Ti
_4-x
Ag
_x
O
₁₂
ceramics are all negative, which indicates that the crystal structures of all ceramics are thermodynamically stable. Pure CaCu
₃
Ti
₄
O
₁₂
ceramic has semiconductor properties, and the spin up and spin down energy band gaps of cubic CaCu
₃
Ti
₄
O
₁₂
ceramic at the high symmetry point Γ are 1.1891eV and 0.8527eV, respectively. After doping silver, however, the CaCu
₃
Ti
_4-x
Ag
_x
O
₁₂
ceramics show metallic properties. The optical properties such as dielectric function, reflectivity, refractive index, photoconductivity, extinction coefficient, absorption coefficient and energy loss function are also discussed.