title: Atomic Resolution Interfacial Structure of Lead-free Ferroelectric K0.5Na0.5NbO3Thin films Deposited on SrTiO3.
abstract: Oxide interface engineering has attracted considerable attention since the discovery of its exotic properties induced by lattice strain, dislocation and composition change at the interface. In this paper, the atomic resolution structure and composition of the interface between the lead-free piezoelectric (K0.5Na0.5)NbO3(KNN) thin films and single-crystalline SrTiO3substrate were investigated by means of scanning transmission electron microscopy (STEM) combining with electron energy loss spectroscopy (EELS). A sharp epitaxial interface was observed to be a monolayer composed of Nb and Ti cations with a ratio of 3/1. The First-Principles Calculations indicated the interface monolayer showed different electronic structure and played the vital role in the asymmetric charge distribution of KNN thin films near the interface. We also observed the gradual relaxation process for the relatively large lattice strains near the KNN/STO interface, which remarks a good structure modulation behavior of KNN thin films via strain engineering.
authors.affiliation: Electronic Materials Research Laboratory, Key Laboratory of The Ministry of Education&International Center for Dielectric Research, Xi'an Jiaotong University, Xi'an, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Li
authors.affiliation: Electronic Materials Research Laboratory, Key Laboratory of The Ministry of Education&International Center for Dielectric Research, Xi'an Jiaotong University, Xi'an, China.
authors.forename: Lingyan
authors.initials: L
authors.lastname: Wang
authors.affiliation: Frontier Institute of Science and Technology, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, China.
authors.forename: Zhao
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Frontier Institute of Science and Technology, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, China.
authors.forename: Yaodong
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Electronic Materials Research Laboratory, Key Laboratory of The Ministry of Education&International Center for Dielectric Research, Xi'an Jiaotong University, Xi'an, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Ren
authors.affiliation: Electronic Materials Research Laboratory, Key Laboratory of The Ministry of Education&International Center for Dielectric Research, Xi'an Jiaotong University, Xi'an, China.
authors.forename: Guang
authors.initials: G
authors.lastname: Yang