Ab initio study of shear strain effects on ferroelectricity at PbTiO3 thin films

► The ferroeletricity (FE) depends on the terminated surfaces of the PbTiO3 thin film. ► In PbO, TiO2 terminated (1 × 1) models, FE is enhanced under the positive shear strain. ► In PbO, TiO2 terminated (1 × 1) models, FE is suppressed under the negative one. ► In PbO terminated c(2 × 2), in PbO layers, FE is enhanced under both shear strains. ► The ideal strength of PbTiO3 thin film is smaller than that of the PbTiO3 bulk.