The Electrical and Magnetic Properties of a Novel Two-Dimensional Antiferromagnet Based on BEDT–TTF: θ-(BEDT–TTF)2Cu2(CN)[N(CN)2]2
The Electrical and Magnetic Properties of a Novel Two-Dimensional Antiferromagnet Based on BEDT–TTF: θ-(BEDT–TTF)2Cu2(CN)[N(CN)2]2
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基于BEDT-TTF的新型二维反铁磁体的电学和磁学性质：θ-(BEDT-TTF)2Cu2(CN)[N(CN)2]2
DOI：
10.1246/bcsj.68.2233
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发表时间：
1995
影响因子：
4
通讯作者：
S. Kagoshima
中科院分区：
文献类型：
--
作者：
T. Komatsu;H. Sato;Toshikazu Nakamura;N. Matsukawa;H. Yamochi;G. Saito;M. Kusunoki;Ken;S. Kagoshima
对新型 BEDT-TTF 盐 θ-(BEDT-TTF)2Cu2(CN)[N(CN)2]2 进行了晶体结构分析和能带计算，以及电导率、热电势、ESR 和静态磁化率测量。这种盐具有独特的聚合阴离子，包含由无序 CN 基团桥接的无限 Cu-N(CN)2-Cu 双螺旋。尽管晶体学上等效的 BEDT-TTF+0.5 阳离子的二维排列在紧束缚近似内提供了二维闭合费米面，但这种盐即使在室温下也具有半导体性，这可能是由于该系统中具有很强的电子相关性。在 220 K 左右观察到半导体-半导体转变。低于 220 K 时，电子系统表示为莫特绝缘体和二维海森堡反铁磁体。 ESR 线宽和自旋磁化率在 50 K 以下快速减小表明存在额外的磁转变。
A crystal-structure analysis and a band calculation, as well as conductivity, thermoelectric power, ESR, and static susceptibility measurements were performed on the new BEDT–TTF salt, θ-(BEDT–TTF)2Cu2(CN)[N(CN)2]2. This salt has a unique polymerized anion comprising infinite Cu–N(CN)2–Cu double helices bridged by disordered CN groups. Although the two-dimensional arrangement of crystallographically equivalent BEDT–TTF+0.5 cations provides a two-dimensional closed Fermi surface within the tight-binding approximation, this salt is semiconductive even at room temperature, probably due to a strong electron correlation in this system. A semiconductor–semiconductor transition has been observed around 220 K. Below 220 K the electronic system is represented as a Mott insulator and a two-dimensional Heisenberg antiferromagnet. Rapid decreases in the ESR line width and spin susceptibility below 50 K indicate the existence of an additional magnetic transition.