First-principles investigation of carbon substitution for lead in ferroelectric lead titanate

Lead titanate, a room-temperature ferroelectric, dielectric material, is of great interest for technological applications. Defects play an important role upon its properties, such as remnant polarization, motion of domain walls, dielectric constant and leakage current, and organic species present during growth make carbon a key impurity. This paper presents a first principles study of the structural and electronic properties of carbon substituting for lead in tetragonal lead titanate. Highly characteristic vibrational modes are predicted to provide a route to experimental identification.