Component-specific electromechanical response in a ferroelectric/dielectric superlattice

作     者：Ji Young Jo Rebecca J. Sichel Eric M. Dufresne Ho Nyung Lee Serge M. Nakhmanson Paul G. Evans 

作者机构：Department of Materials Science and Engineering and Materials Science Program University of Wisconsin–Madison Madison Wisconsin 53706 USA Advanced Photon Source Argonne National Laboratory Argonne Illinois 60439 USA Materials Science and Technology Division Oak Ridge National Laboratory Oak Ridge Tennessee 37831 USA Materials Science Division Argonne National Laboratory Argonne Illinois 60439 USA 

出 版 物：《Physical Review B》 (物理学评论B辑：凝聚态物质与材料物理学)

年 卷 期：2010年第82卷第17期

页      面：174116-174116页

核心收录：

学科分类：07[理学] 0702[理学-物理学] 

基　　金：U.S. Department of Energy [DE-FG02-04ER46147, DE-AC02-06CH11357] U.S. National Science Foundation [DMR-0705370] Materials Sciences and Engineering Division, U.S. Department of Energy [DE-AC05-00OR22725] Direct For Mathematical & Physical Scien Division Of Materials Research Funding Source: National Science Foundation U.S. Department of Energy (DOE) [DE-FG02-04ER46147] Funding Source: U.S. Department of Energy (DOE) 

摘      要：The electronic and electromechanical properties of complex oxide superlattices are closely linked to the evolution of the structure and electrical polarization of the component layers in applied electric fields. Efforts to deduce the responses of the individual components of the superlattice to applied fields have focused on theoretical approaches because of the limitations of available experimental techniques. Time-resolved x-ray microdiffraction provides a precise crystallographic probe of each component using the shift in wave vector and change in intensity of superlattice satellite reflections. We report in detail the methods to measure and analyze the x-ray diffraction patterns in applied electric field and their application to a 2-unit-cell BaTiO3/4-unit-cell CaTiO3 superlattice. We find that the overall piezoelectric distortion is shared between the two components. Theoretical predictions of the electromechanical properties of a superlattice with the same composition constrained to tetragonal symmetry are in excellent agreement with the experiments. Lattice instability analysis, however, suggests that the low-temperature ground state could exhibit antiferrodistortive rotations of TiO6 octahedra within and/or at the interfaces of the CaTiO3 component.