The impacts of strain and polar discontinuities on the performance of superlattices have attracted widespread attention. Using first-principles calculation, we study the polarization and piezoelectricity of PbTiO3/KTa...The impacts of strain and polar discontinuities on the performance of superlattices have attracted widespread attention. Using first-principles calculation, we study the polarization and piezoelectricity of PbTiO3/KTa03 （PTO//KTO） superl^ttices with strain and polsr discontinuities. The strain caused by lattice mismatch between the superlattice and the substrate induces lattice distortion, the displacement of each atom and dynamical charge transfer between the Ti atom or Ta atom and the 0 atoms in the PTO//KTO superlattice. With more compressive or less tensile strain, the polarization value increases linearly, piezoelectric tensor e31 （e32） increases while e33 and e25 （e16） increase negatively. Polarity discontinuity caused by the interracial charge will produce large irreversible polarization. Proved by F-point phonons of PTO//KTO superlattices of different strain values, the polar discontinuity and the piezoelectric properties are just weakly dependent on temperature as found in PTO//KTO superlattices.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 11372085 and 10902029the Shenzhen Science and Technology Project under Grant No JCYJ20150625142543461
文摘The impacts of strain and polar discontinuities on the performance of superlattices have attracted widespread attention. Using first-principles calculation, we study the polarization and piezoelectricity of PbTiO3/KTa03 （PTO//KTO） superl^ttices with strain and polsr discontinuities. The strain caused by lattice mismatch between the superlattice and the substrate induces lattice distortion, the displacement of each atom and dynamical charge transfer between the Ti atom or Ta atom and the 0 atoms in the PTO//KTO superlattice. With more compressive or less tensile strain, the polarization value increases linearly, piezoelectric tensor e31 （e32） increases while e33 and e25 （e16） increase negatively. Polarity discontinuity caused by the interracial charge will produce large irreversible polarization. Proved by F-point phonons of PTO//KTO superlattices of different strain values, the polar discontinuity and the piezoelectric properties are just weakly dependent on temperature as found in PTO//KTO superlattices.
