Quasi-Low-Dimensional Reduced Transition Metal Oxides: Synthesis and Characterization

9314605 Greenblatt经验表明，当存在竞争性电子相互作用时，可能会发现具有新颖行为的材料。在低维材料中，竞争电子相互作用的相互作用增强。本项目的目标是合成和表征具有准低维性质的新型还原过渡金属化合物。感兴趣的系统包括：（1）过渡金属（Nb，Ta和W）青铜和（2）钼，铌和铌簇化合物。实验计划的重点是合成处于电子和结构不稳定性边缘的强相关电子系统的新材料，并以可控的方式通过不稳定区域微调竞争电子相互作用。特别强调将放在单晶试样的制备，以研究结构和取向依赖的物理性能。电阻率、磁化率、比热随温度变化的单晶测量、DTA、ESR、FTIR、光学和XANE光谱将用于表征感兴趣的样品。将强调结构和物理性质的关系。与电荷密度波（CDW）和/或超导性的发病过渡将寻求和特点。这些研究有望产生新的材料，提供相关的电子行为的基本见解和uHierarchy允许增强和控制电子不稳定性，导致有趣的和有用的宏观性能。 ***

9314605 Greenblatt Experience shows that materials with novel behavior are likely to be discovered when competing electronic interactions exist. In low-dimensional materials, the interplay of competing electronic interactions is enhanced. The object of this project is the synthesis and characterization of new reduced transition metal compounds with quasi-low-dimensional properties. Systems of interest include: (1) transition metal (Nb, Ta and W) bronzes and (2) molybdenum, niobium, and rhenium cluster compounds. The focus of the experimental program is to synthesize new materials of strongly-correlated electron systems that are on the verge of electronic and structural instabilities, and to fine tune the competing electronic interactions through the unstable region in a controlled way. Particular emphasis will be placed on the preparation of single crystal specimens to study the structural and orientation dependent physical properties. Single crystal measurements of the electrical resistivity, magnetic susceptibility, specific heat as a function of temperature, DTA, ESR, FTIR, optical and XANE spectroscopies will be used to characterize samples of interest. Structural and physical property relationships will be stressed. Transitions associated with the onset of charge density waves (CDW) and/or superconductivity will be sought and characterized. These studies are expected to yield novel materials, provide fundamental insights into correlated electronic behavior and uHimately allow the enhancement and control of electronic instabilities that lead to interesting and useful macroscopic properties. ***