A nonlinear thermodynamic formalism is developed to calculate the pyroeletric property of epitaxial single domain SrTiO_(3)/Si heterojunctions by taking into account the thermal expansion misfit strain at diferent tem...A nonlinear thermodynamic formalism is developed to calculate the pyroeletric property of epitaxial single domain SrTiO_(3)/Si heterojunctions by taking into account the thermal expansion misfit strain at diferent temperatures.It has been demonstrated that the crucial role was played by the contribution associated with the structure order parameter arising from the rotations of oxygen octahedral on pyroelectricity.A dramatic decrease in the pyroelectric cofficient due to the strong coupling between the polarization and the structure order parameter is found at ferroelectric T_(p1)-T_(p2) phase transition.At the same time,the thermal expansion mismatch between film and substrate is also found to provide an additional weak decrease of pyroelectricity.The analytic relationship of the out-of-plane pyroeletric coefficient and dielectric constant of ferroeletric phases by considering the thermal expansion of thin films and substrates has been determined for the first time.Our research provides another avenue for the investigation of the pyroelectric effects of ferroic thin films,especially,such as antiferroelectric and muliferroic materials having two or more order parameters.展开更多
基金supported by National Natural Science Foundation of China(Grant No.11134004,51372111,11404169,11304158,61306098)Nanjing University of Posts and Telecommunications Research Fund(NY213080,NY214046 and NY215006)National Laboratory of Solid State Microstructures Open Fund of Nanjing University(M28006 and M28034).
文摘A nonlinear thermodynamic formalism is developed to calculate the pyroeletric property of epitaxial single domain SrTiO_(3)/Si heterojunctions by taking into account the thermal expansion misfit strain at diferent temperatures.It has been demonstrated that the crucial role was played by the contribution associated with the structure order parameter arising from the rotations of oxygen octahedral on pyroelectricity.A dramatic decrease in the pyroelectric cofficient due to the strong coupling between the polarization and the structure order parameter is found at ferroelectric T_(p1)-T_(p2) phase transition.At the same time,the thermal expansion mismatch between film and substrate is also found to provide an additional weak decrease of pyroelectricity.The analytic relationship of the out-of-plane pyroeletric coefficient and dielectric constant of ferroeletric phases by considering the thermal expansion of thin films and substrates has been determined for the first time.Our research provides another avenue for the investigation of the pyroelectric effects of ferroic thin films,especially,such as antiferroelectric and muliferroic materials having two or more order parameters.
