电荷密度波到Mott-Hubbard相位过渡在准一维桥式Pd化合物中的电荷密度波
Shinya Takaishi1, Mitsuhito Takamura, Takashi Kajiwara
1Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aza-aoba, Aramaki, Sendai 980-8578, Japan. takaishi@agnus.chem.tohoku.ac.jp
Journal of the American Chemical Society
|August 19, 2008
概括
研究人员在一个近乎一维的-化合物中发现了一个新的Mott-Hubbard状态. 这种状态表现出相位过渡到电荷密度波形状态,受到来自 counterions 的化学压力的影响.
科学领域:
- 凝聚物质物理学 凝聚物质物理学
- 材料科学 材料科学 材料科学
- 固态化学 固态化学
背景情况:
- 桥金属化合物表现出令人着迷的电子特性.
- 几乎一维的系统对于理解电荷运输现象至关重要.
- 莫特-哈巴德和电荷密度波态代表固体中不同的电子相.
研究的目的:
- 为了研究准一维桥化合物中的电子状态.
- 在这样的系统中识别和描述一个Mott-Hubbard状态.
- 探索Mott-Hubbard和电荷密度波态之间的相位过渡.
主要方法:
- 准一维桥化合物的合成,特别是[Pd(en) 2Br](C5-Y) 2 x H2O.
- 用X射线衍射和拉曼光谱分析结构和振动特性.
- 电子自旋共振 (ESR),电子光谱,电电阻和热容量测量以探测电子状态和相位过渡.
主要成果:
- 第一次观察 -Pd(III) -Br-Pd(III) -Mott-Hubbard状态在一个近乎一维的桥式合物中.
- 在Mott-Hubbard和电荷密度波状态之间的相位过渡在206 +/- 2K时被确定.
- 化学压力,由 counterions ([Pd(en) 2Br](C(n) -Y) 2 x H2O (n=4-9,12) 的变异链长度诱导,被证实是阶段过渡的驱动因素.
结论:
- 这项研究成功地确定和描述了一种新型的Mott-Hubbard状态,在一个近乎一维的桥式系统中.
- 观察到的相变可以通过化学压力调节,为材料设计提供了一条途径.
- 这项研究为低维材料的结构和电子相之间的相互作用提供了基本的见解.
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