Charge Transport in Charge-Ordered States of Two-Dimensional Organic Conductors, alpha-(BEDT-TTF)_2I_3 and alpha
Charge Transport in Charge-Ordered States of Two-Dimensional Organic Conductors, alpha-(BEDT-TTF)_2I_3 and alpha
复制标题
二维有机导体 alpha-(BEDT-TTF)_2I_3 和 alpha 的电荷有序状态下的电荷传输
DOI：
10.1143/jpsj.81.044703
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
K.Kodama
中科院分区：
文献类型：
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作者：
渡邊美穂;白旗 崇;御崎洋二;鎌田賢司;K.Kodama
测量了准二维有机导体α-（BEDT-TTF）_2I_3和α ′-（BEDT-TTF）_2IBr_2电荷有序态的电导和介电常数，以了解其电荷输运机制.的电流-电压（I-V）特性表现出很强的非线性行为，这是定性地解释了从BEDT-TTF层中的电荷有序态热激发的单个载流子的运输。与基于低温下的热激活模型的模拟的差异可能是由于量子隧穿通过势垒。样品的介电常数在面内和面外方向上有很大的差异，表明库仑势具有高度的二维性。介电常数的温度依赖性归因于热激发电子-空穴对的极化效应，与非线性I-V特性模型一致。尽管α-（BEDT-TTF）_2I_3和α ′-（BEDT-TTF）_2IBr_2的结构和磁性不同，但它们的这些性质在性质上是相同的。
Electric conductance and dielectric constant have been measured in the charge-ordered states of the quasi two-dimensional organic conductors α-(BEDT-TTF)2I3and α'-(BEDT-TTF)2IBr2to understand the charge transport mechanism. The current–voltage (I–V) characteristics show a strong nonlinear behavior, which is qualitatively explained by the transport of individual carriers thermally excited from the charge-ordered states in BEDT-TTF layers. The discrepancy with the simulation based on the thermal activation model at low temperatures is likely due to quantum tunneling through the potential barrier. The dielectric constants show a large difference between the in-plane and out-of-plane directions of the samples, showing a highly two-dimensional nature of Coulomb potential. The temperature dependence of dielectric constant is ascribed to the polarization effect of the thermally excited electron–hole pairs, consistent with the model of nonlinearI–Vcharacteristics. All these features are qualitatively the same between α-(BEDT-TTF)2I3and α'-(BEDT-TTF)2IBr2, despite the different structural and magnetic properties.