First Principles Study of Dopant Site Selectivity in Ordered Perovskite CaCu₃Ti₄O₁₂

We investigate the dopant site selectivity of CaCu₃Ti₄O₁₂ (CCTO) using the first principles calculations. Our results show that, for four cases of possible occupancy by La atom, lattice expansions and formation enthalpies with different dopant quantities indicate that doped La cations are preferentially substituted for Ca sites in CaCu₃Ti₄O₁₂, which is excellent in agreement with the experimental observation (Choi et al. Adv. Mater. 21 (2009) 885). Furthermore, more interesting information of doping is also explored by the analysis of density of states and it is found that La substituting for Cu may advance the electron conduction in CCTO. It supplies a potential solution for limitations of CCTO devices by exploring the effect when La substitutes for Cu sites in the CCTO crystal.