Organic conductors based on the unsymmetrical Ï donor molecule EDT-TTF (ethylenedithiotetrathiafulvalene) or its selenium-substituted analogs (EDST, EDTS) and tetrahedral anions GaCl
4
â
were prepared. The crystal structure determinations and the extended Hückel tight-binding band calculations indicate these systems to be quasi-one-dimensional conductors similar to TMTTF or TMTSF systems (TM systems). Electrical resistivity and magnetic susceptibility measurements and low-temperature X-ray diffraction experiments suggested a spin-Peierls ground state for (EDT-TTF)
2
GaCl
4
. (EDST)
2
GaCl
4
and (EDTS)
2
GaCl
4
exhibit metallic behavior down to ca. 40Â K. The electric and magnetic properties of (EDST)
2
GaCl
4
suggested a semimetallic state at low temperature. In spite of the similarity in the crystal and electronic band structures between TM and EDT systems, these two series of quasi-one-dimensional conductors do not share the same âgeneralized phase diagramâ. The electronâlattice interaction seems to be important in EDT conductors. The electric and magnetic properties of the isostructural systems with magnetic FeCl
4
â
anions were also examined. The magnetic interaction between the high-spin Fe
3+
ions was found to be very weak.
基于非对称Ï供体分子EDT-
TTF(乙二
硫四
硫富
戊烯)或其
硒取代类似物(EDST、ED
TS)和四面体阴离子GaCl 4 â制备了有机导体。晶体结构测定和扩展 H¼ckel 紧约束带计算表明,这些系统是类似于
TMTTF 或
TMTSF 系统(TM 系统)的准一维导体。电阻率和磁感应强度测量以及低温 X 射线衍射实验表明,(EDT-
TTF) 2 GaCl 4 具有自旋-Peierls 基态。 (EDST) 2 GaCl 4 和 (ED
TS) 2 GaCl 4 在低至约 40Â K 的温度下表现出
金属特性。尽管 TM 和 EDT 系统的晶体和电子能带结构相似,但这两个系列的准一维导体并不共享相同的 "广义相图"。在 EDT 导体中,电子与晶格的相互作用似乎非常重要。我们还研究了带有磁性FeCl 4 - 阴离子的等结构体系的电学和磁学性质。研究发现,高自旋 Fe 3+ 离子之间的磁性相互作用非常微弱。