Interplay between intrinsic defects, doping, and free carrier concentration in SrTiO 3 thin films

Using both computational and experimental analysis, we demonstrate a rich point-defect phase diagram in doped strontium titanate as a function of thermodynamic variables such as oxygen partial pressure and electronic chemical potential. Computational modeling of point-defect energetics demonstrates that a complex interplay exists between dopants, thermodynamic parameters, and intrinsic defects in thin films of SrTiO 3 (STO). We synthesize STO thin films via pulsed laser deposition and explore this interplay between intrinsic defects, doping, compensation, and carrier concentration. Our point-defect analysis (i) demonstrates that careful control over growth conditions can result in the tunable presence of anion and cation vacancies, (ii) suggests that compensation mechanisms will pose intrinsic limits on the dopability of perovskites, and (iii) provides a guide for tailoring the properties of doped perovskite thin films. © 2012 American Physical Society.