複雜氧化物介面交互作用之控制

Abstract

In this thesis, we investigated control the interactions of complex oxide interfaces. Hetero-interfaces between complex oxides have sparked considerable interest due to their fascinating physical properties and offer new possibilities for next-generation electronic devices. While most studies are aiming at exploring new interfaces by combining different materials, another key to realizing the practical applications is the control through external stimulus. As the first subject, we propose a generic approach to use an additional layer, e.g. ferroelectric Pb(Zr0.2Ti0.8)O3, on LaAlO3 (LAO)/SrTiO3 (STO) interface as a nonvolatile modulation of the conduction behaviors at this interface. In order to reveal the insight, the change of the interface band structure was comprehensively investigated by a combination of the ferroelectric pattern assisted x-ray photoelectron spectroscopy and scanning tunneling spectroscopy. This study opens an avenue to the nonvolatile control of complex oxide interfaces. Moreover, in strongly correlated oxides, heterointerfaces provide a powerful route to manipulate the charge, spin, orbital, and lattice degrees of freedom to create new functionalities. As the second part of study, the ferromagnetic (F) La2/3Ca1/3MnO3(LCMO)/superconducting (S) YBa2Cu3O7-x (YBCO) heterostructures of two distinct interfaces with atomically precise interface control have been fabricated to explore the interactions between these two functional layers. A new mechanism of charge transfer in these heterostructures was identified. This charge transfer, in addition to the previously considered F/S proximate effect, is critical to the superconductivity, magnetism, and x-ray absorption spectroscopy observed in these heterostructures

In this thesis, we investigated control the interactions of complex oxide interfaces. Hetero-interfaces between complex oxides have sparked considerable interest due to their fascinating physical properties and offer new possibilities for next-generation electronic devices. While most studies are aiming at exploring new interfaces by combining different materials, another key to realizing the practical applications is the control through external stimulus. As the first subject, we propose a generic approach to use an additional layer, e.g. ferroelectric Pb(Zr0.2Ti0.8)O3, on LaAlO3 (LAO)/SrTiO3 (STO) interface as a nonvolatile modulation of the conduction behaviors at this interface. In order to reveal the insight, the change of the interface band structure was comprehensively investigated by a combination of the ferroelectric pattern assisted x-ray photoelectron spectroscopy and scanning tunneling spectroscopy. This study opens an avenue to the nonvolatile control of complex oxide interfaces. Moreover, in strongly correlated oxides, heterointerfaces provide a powerful route to manipulate the charge, spin, orbital, and lattice degrees of freedom to create new functionalities. As the second part of study, the ferromagnetic (F) La2/3Ca1/3MnO3(LCMO)/superconducting (S) YBa2Cu3O7-x (YBCO) heterostructures of two distinct interfaces with atomically precise interface control have been fabricated to explore the interactions between these two functional layers. A new mechanism of charge transfer in these heterostructures was identified. This charge transfer, in addition to the previously considered F/S proximate effect, is critical to the superconductivity, magnetism, and x-ray absorption spectroscopy observed in these heterostructures