Control of Multipolar and Orbital Order in Perovskite-like [C(NH2)3]CuxCd1-x(HCOO)3 Metal-Organic Frameworks
Control of Multipolar and Orbital Order in Perovskite-like [C(NH2)3]CuxCd1-x(HCOO)3 Metal-Organic Frameworks
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DOI：
10.1021/jacs.6b05208
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发表时间：
2016-08-03
影响因子：
15
通讯作者：
Goodwin, Andrew L.
中科院分区：
文献类型：
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作者：
Evans, Nicole L.;Thygesen, Peter M. M.;Goodwin, Andrew L.
研究了钙钛矿类金属有机骨架[C(NH2)(3)]CuxCd1-x(HCOO)(3)中分子取向（多极）和轨道（四极）顺序的组成依赖性。当增加jahn - teller活性Cu2+的分数x时，我们观察到轨道无序/有序转变和多极重定向转变，分别发生在不同的临界成分x(o) = 0.45(5)和x(m) = 0.55(5)。我们将这些转变归因于尺寸、电荷分布和渗透效应的结合。我们的结果建立了新的结构自由度的甲酸钙钛矿的可及性超越了熟悉的偶极项负责（反）铁电秩序。我们讨论了四极态和多极态的协同作用对类弛豫杂化钙钛矿设计的意义。
We study the compositional dependence of molecular orientation (multipolar) and orbital (quadrupolar) order in the perovskite-like metal organic frameworks [C(NH2)(3)]CuxCd1-x(HCOO)(3). Upon increasing the fraction x of Jahn-Teller-active Cu2+, we observe an orbital disorder/order transition and a multipolar reorientation transition, each occurring at distinct critical compositions x(o) = 0.45(5) and x(m), = 0.55(5). We attribute these transitions to a combination of size, charge distribution, and percolation effects. Our results establish the accessibility in formate perovskites of novel structural degrees of freedom beyond the familiar dipolar terms responsible for (anti)ferroelectric order. We discuss the implications of cooperative quadrupolar and multipolar states for the design of relaxor-like hybrid perovskites.