The effect of domain walls on leakage current in PbTiO3 thin films

• The domain walls play important roles for the leakage current in the ferroelectric thin films.
• The leakage current is enhanced by 2 or 3 orders for the occurrences of the 180° domain in ultrathin PTO film.
• The leakage current enhancement owes to the additional transport channels induced by the 180° domain wall.

Combining nonequilibrium Green function's approach with density functional theory, the effects of the 180° domain walls on the leakage current of PbTiO3 (PTO) thin films have been investigated. It is found that the leakage current of the ultrathin PTO film with 180° domain walls is greatly increased compared with that of perfect PTO film. Moreover, we found that the effect of domain walls on the leakage current in TiO2-terminated PTO films is larger than that in PbO-terminated PTO films. The enhancement of the leakage current is mainly attributed to the extra transport channels introduced by the domain walls according to the calculated transmission coefficient and the band structures. These results suggest that the leakage current of ferroelectric thin films can be decreased by controlling the occurrence of domain walls and their orientation in the design of nanoscale electronic devices.