强关联氧化物体系的应力调制及多场耦合效应

The present proposal will focus our attention on strain modulation and multi-field coupling effect in strongly correlated electronic perovskite oxide, such as CMR, multiferric and superconducting oxide et al. A series of epitaxial single crystal films will be grown by pulse laser deposition technique on the piezoelectric and piezomagnetic substrates, including various electron doping concentration, superconductor/insulator heterostructure films with different magnetic configuration and phase separation features films. In order to realize the effective modification of compressive and tensile strain in the special directions of the films under electric and magnetic fields, we would choose the PMN-PT and Teflon-D single crystal substrates with the largest electric polarization and rather large magnetostriction. Effect of dynamic strain-modification on the films could provide some direct evidences on important science questions, such as the novel physical properties, electronic structure, electron-hole symmetry, insulator-metal/superconductivity transition, Kondo-like spin scattering, proximate and interface effects and so on from the low temperature and high magnetic field experiments. At the same time, the structural analysis and theoretical simulation approaches will also be done. And the comparative studies will be necessary for polycrystalline and single crystal bulk samples.Our results will be helpful to understanding the physical mechanism and could also provide some important basic research data and experimental evidences.

本课题以应力调制对强关联氧化物体系的物性和相结构影响为基本内容，通过在具有压电和压磁特性的单晶衬底上生长系列薄膜样品，包括具有不同掺杂浓度、不同磁结构和相分离特征的单层或多层异质结构薄膜，选用具有最大电极化特性的PMN-PT和大磁致伸缩系数的Teflon-D且具有不同取向的单晶压电和压磁基片，以保证在特定方向实现外加电场和磁场下的压应力和张应力对薄膜的有效调制，以低温和强磁场下的物性测量为主要手段，辅之以结构分析和理论模拟等手段相结合，并与单晶、多晶及相关氧化物进行对比研究，探讨应力与电场磁场等多场耦合调制所表现出的新奇物性，以期为解决包括应力调制对以CMR、多铁和超导等为代表的强关联氧化物体系物性和相结构的影响、电子之间的强关联效应、电子-空穴对称性、绝缘-金属转变、低温自旋关联输运、近邻效应与界面效应等基本问题提供例证，为强关联氧化物物理机制的理解提供有价值的基础研究资料。

该项目主要研究了强关联钙钛矿氧化物体系的应力调制效应及其对物性的影响，通过对具有不同掺杂浓度、不同磁结构和相分离特征的单晶、多晶及薄膜等不同形态的样品体系的对比性研究，以低温和强磁场下的磁电特性等物性测量及其与结构特征之间的关联，与适当的理论计算相结合，探讨电场磁场力场等多场耦合调制所表现出的新奇物性，以期为解决包括对以CMR、多铁和超导等为代表的强关联氧化物体系物性和相结构的影响、电子之间的强关联效应、电子-空穴对称性、绝缘-金属转变、低温自旋关联输运、近邻效应与自旋重取向相变等基本问题提供重要的实验资料，为强关联氧化物体系物理机制的理解提供有价值的实验和理论证据。以该项目为基础，我们也拓展研究思路开展了在材料基因组理念下高通量材料制备和结构表征，以及利用人工智能机器学习手段开展数据驱动材料研究的探索性工作，以其为未来研究提供一些新思路和新方法。