氧空位及氧空位长程有序对过渡金属氧化物异质结构新奇物性的调控

The symmetry is broken and the dimension is limited at the interface of the transition-metal oxide heterostructures, and the association between the electron charge/spin/orbit/lattice is more apparent, therefore the transition-metal oxide heterostructures show many novel electrical, magnetic, and optical characteristics. To the central issue of the regulation of the oxygen vacancies and the long-range ordering of the oxygen vacancies on the novel properties of the transitional-metal oxide heterostructures, many kinds of the transitional-metal oxide heterostructures, including thin films, heterojunctions, and superlattices, were fabricated by laser molecular beam epitaxial, and the concentration of the oxygen vacancies was well-controlled. The effect of the regulation of the oxygen vacancies on the oxide heterostructures were investigated in electric field, magnetic field, light field and temperature field, and their physical mechanisms were analyzed. By varying the doping concentration of the transition metals, the effects of the structures of the electrons and spins of the transitional metal on the properties were studied. By using state-of-the-art sophisticated aberration-corrected scanning transmission electron microscopy (STEM) techniques, synchrotron x-ray diffractometry and x-ray spectrometry, and first-principle calculation, from the micro and macro aspects, and from the two kinds of experimental methods of the theory and experiment, the basic physics problems and physical essences of the regulation of the oxygen vacancies and the long-range ordering of the oxygen vacancies on the properties of electric, magnetic and optical. To provide the experimental basis for understanding the physical mechanism of the regulation of oxygen vacancies on the oxide heterostructures and the development of new oxide electronic devices.

过渡金属氧化物异质结构中由于界面处对称性破缺和维度受限，以及电子电荷/自旋/轨道/晶格之间的关联作用更加明显,氧化物异质结呈现出的新奇的电、磁、光特性。针对氧空位及氧空位长程有序对过渡金属氧化物异质结构新奇物性调控这一中心问题，用激光分子束外延技术精控制备多种过渡金属氧化物异质结构（薄膜、异质结、超晶格），并控制氧空位浓度。研究在电场、磁场、光场、温度等外场下氧空位对氧化物异质结构电-磁-光耦合特性的调控效应，并分析其物理机理。改变过渡金属的掺杂浓度，研究过渡金属的电子结构和自旋结构对氧化物异质结构的性质的影响。应用先进的球差校正电镜技术，同步辐射衍射和能谱技术，以及第一性原理计算，从微观和宏观两个方面，以及从理论和实验两种实验方法上，揭示氧空位及氧空位长程有序对氧化物异质结构电-磁-光等物性调控的基本物理问题和物理本质。为理解氧空位调控氧化物异质结构的物理机制以及新型氧化物电子器件的研发

针对氧空位及氧空位长程有序对过渡金属氧化物异质结构新奇物性调控这一中心问题，我们制备了氧空位含量变化的La0.7Sr0.3MnO3薄膜、La0.7Sr0.3MnO3/Ba0.7Sr0.3TiO3超晶格、氧空位有序的SrCoOx薄膜等氧化物低维结构。我们通过在制备过程中控制氧压的不同而控制La2/3Sr1/3MnO3薄膜中氧含量的多少，揭示了氧空位调控La2/3Sr1/3MnO3物性的微观机制。我们制备了不用氧空位浓度的SrCoOx(2.5 ≤ x ≤ 3)薄膜，研究了应力对SrCoOx薄膜的结构和电子结构的调控效应。接着，我们发现氧空位对氧化物/钙钛矿界面的光电转换有关键性影响，解释了钙钛矿电池的洄滞现象。分别在Chemistry of Materials, Advanced Functional Materials, ACS Applied Materials & Interfaces、Advanced Materials Interfaces, Physical Review B等期刊上发表共发布SCI论文21篇，申请专利9个，获得授权3个。本项目执行期间，共培养在读博士研究生1人，硕士研究生10人，毕业博士5人，毕业硕士2。本项目负责人获得河南省高校创新团队支持。