Control of non-linear self-localization phenomena of strongly coupling charge carriersin LiNb_(1-x)Ta_xO_3 (LNT) - solid solutions

LiNb_(1-x)Ta_xO_3 (LNT) 固溶体中强耦合载流子非线性自定位现象的控制

• 批准号: 449904011
• 负责人: Professor Dr. Mirco Imlau
• 金额: --
• 依托单位: Institute for Solid State Physics and Optics
• 依托单位国家: 德国
• 项目类别: Research Units
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/449904011?language=en
• 关键词: Control; non; linear; self; localization

The proposal is part of the research group 'Periodic low-dimensional defect structures in polar oxides', which is dedicated to the correlation of defect structure, electron and ion transport and electromechanical properties using the model system lithium niobate-lithium tantalate (LiNb_(1-x)Ta_x)O_3, LNT). The focus of this subproject is the interaction of strongly coupling charge carriers with (i) the structural, atomistic properties of the solid solution system, (ii) the dielectric and structural properties of ferroelectric domain walls, and (iii) the transport properties of ionic diffusion at elevated temperatures. Thus, the project aims to address the question of the role of structural, electronic and ionic properties in self-localization mechanisms in dielectric, oxide solid state materials in general. Specifically for the solid solution system LNT, it is expected that with the extended knowledge, possibilities for a tailored control of the self-localization of charge carriers by adjusting the composition, by domain structuring and temperature can be worked out. From an application-oriented point of view, e.g. non-linear photonics or nano-optoelectronics, this is connected with the question of possibilities for extensive control of (non-)linear optical and electronic properties. From a methodological point of view, the processing of this objective requires (a) the systematic application of established methods of nonlinear optical, time-resolved spectroscopy in the ultraviolet and visible spectral range on time scales from sub-picoseconds to the second range, (b) their extension by the aspect of spatially resolved studies on the micrometer length scale and (c) their application at temperatures above room temperature. This is associated with the correlative combination of nonlinear optical wide-field and confocal microscopy with excitation-scan spectroscopy and the installation of a temperature cell with a controllable oxygen content. The experimental results on LNT crystals of different composition and doping, ferroelectrically monodomain or periodically poled crystal samples, will be reproduced with numerical model calculations on the dynamics of self-localization, transport and recombination processes in the dielectric environment with composition gradients, extended phonon spectrum, lattice defects, domain walls and ionic diffusion. By comparison with atomistic model calculations as well as statistical transport models a correlation between material-specific, experimental and nonlinear optical or electronic parameters will be developed. The project ends with the identification of control possibilities of nonlinear optical, electronic and electromechanical properties based on the self-localization of charge carriers.

该提案是“极性氧化物中的周期性低维缺陷结构”研究小组的一部分，该小组致力于使用铌酸锂-钽酸锂（LiNb_(1-x)Ta_x）O_3， LNT)模型系统研究缺陷结构，电子和离子输运和机电性能的相关性。这个子项目的重点是强耦合载流子与(i)固溶体系统的结构、原子特性，（ii）铁电畴壁的介电和结构特性，以及（iii）高温下离子扩散的输移特性之间的相互作用。因此，该项目旨在解决结构，电子和离子性质在介电，氧化物固体材料的自定位机制中的作用问题。特别是对于固溶体体系LNT，期望通过扩展的知识，可以通过调整组成，结构和温度来定制控制载流子自定位的可能性。从面向应用的角度来看，例如非线性光子学或纳米光电子学，这与广泛控制（非线性）光学和电子特性的可能性问题有关。从方法学的角度来看，这一目标的处理需要(a)在时间尺度从亚皮秒到秒的紫外和可见光谱范围内系统地应用已建立的非线性光学、时间分辨光谱方法，(b)在微米长度尺度上通过空间分辨研究方面进行扩展，(c)在室温以上的温度下应用。这与非线性光学宽视场和共聚焦显微镜与激发扫描光谱的相关组合以及具有可控氧含量的温度电池的安装有关。本文将对不同成分和掺杂的LNT晶体（铁电单畴或周期性极化晶体样品）的实验结果进行再现，并对介电环境中具有成分梯度、扩展声子谱、晶格缺陷、畴壁和离子扩散的自定位、输运和重组过程的动力学进行数值模型计算。通过与原子模型计算以及统计输运模型的比较，将发展出特定材料、实验和非线性光学或电子参数之间的相关性。最后，基于电荷载流子的自定位，确定了非线性光学、电子和机电特性的控制可能性。