Design and Synthesis of Two-Dimensional Organic Conductors

二维有机导体的设计与合成

• 批准号: 06640469
• 负责人: HASEGAWA Tatsuo
• 金额: $ 1.02万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06640469/
• 关键词: Molecular Conductors; Charge Transfer Complex; BEDT-TTF; TCNQ derivative; Band Filling Control; Antiferromagnet; スピン・電荷複合物性; フィリング制御; 電荷移動錯体; 反強磁性相

The advantage of studying the title system is that the acceptors can be designed to have various LUMO levels by chemical modification, which enables us to tune the filling of 2D ET HOMO band. Another notable feature is the existence of local spins on anion radicals, which have the possibility of modulating the 2D conduction layrs.As a first step of this strategy, we chose TCNQ and its fluorinated derivatives, and succeeded in synthesizing (ET) (FnTCNQ), where n=0,1,2,4. Among these, crystals of (ET) (F1TCNQ) display metallic behavior down to 2K.This is the first ET-based two-component system preserving metallic down to 2K.We note that the magnetic susceptibility of (ET) (F1TCNQ) does not show simple Pauli-paramagnetic behavior, but exhibits Curie-like enhancement with decreasing temperature. In (ET) (F2TCNQ) and (ET) (F4TCNQ), a novel type of mixed-stack CT crystals were obtained. They undergo anti-ferromagnetic transition at TN=30K and 14K.These results indicate that neither the Peierls nor spin-Peierls instability to nonmagnetic phases occurs both in two-component system of (ET) (FnTCNQ). Intercolumnar contact of ET molecules plays a crucial role to suppress the 1D instabilities of acceptor columns. Unusual properties of electrical, magnetic, and optical properties of (ET) (FnTCNQ) were clarified.

研究标题系统的优点是可以通过化学修饰将受体设计成具有不同的LUMO能级，这使得我们能够调整2D ET HOMO带的填充。另一个显着的特点是阴离子自由基上存在局部自旋，这具有调节二维传导层的可能性。作为该策略的第一步，我们选择了TCNQ及其氟化衍生物，并成功合成了（ET）（FnTCNQ） ，其中 n=0,1,2,4。其中，(ET) (F1TCNQ) 晶体在低至 2K 时表现出金属行为。这是第一个基于 ET 的双组分系统，在低至 2K 时仍保持金属性。我们注意到 (ET) (F1TCNQ) 的磁化率并不显示出简单的泡利顺磁行为，但随着温度降低而表现出类居里增强。在(ET)(F2TCNQ)和(ET)(F4TCNQ)中，获得了一种新型的混合堆叠CT晶体。它们在TN=30K和14K时经历反铁磁转变。这些结果表明，在(ET)(FnTCNQ)的双组分体系中，对非磁性相的Peierls不稳定性和自旋Peierls不稳定性均不发生。 ET分子的柱间接触对于抑制受体柱的一维不稳定性起着至关重要的作用。 (ET) (FnTCNQ) 的电学、磁学和光学性质的异常特性得到了澄清。