Theoretical study on small clusters of BaTiO3 using DFT calculations

Using density functional theory with the generalised gradient approximation, the structural and electronic properties of small (BaTiO3)n (n = 1–4) clusters have been studied. All the analysed growth modes were observed to consist of the same unit block, which in turn is similar to the well-known (TiO2)2 cluster. The BaTiO3 and (BaTiO3)2 systems were observed to adopt analogous geometries to the ground state of (TiO2)n clusters with Cs and D2h symmetries, respectively. The calculated value of the energy gap for the studied (BaTiO3)n clusters tends to approach that observed for its tetragonal bulk BaTiO3 counterpart when n ≥ 3 is considered; the same tendency is observed for the Ba–Ba, Ba–Ti, Ti–O and Ba–Ti interatomic distances. For all the (BaTiO3)n clusters, the structural characteristics of their respective isomers were explored.