Metal-Insulator Transition of the New One-Dimensional Organic Conductors with Complete Uniform Stacks: (DMEDO-TTF)2X (X = ClO4 and BF4)
Metal-Insulator Transition of the New One-Dimensional Organic Conductors with Complete Uniform Stacks: (DMEDO-TTF)2X (X = ClO4 and BF4)
复制标题
具有完全均匀堆叠的新型一维有机导体的金属-绝缘体转变：(DMEDO-TTF)2X (X = ClO4 和 BF4)
DOI：
10.1103/physrevb.93.245136
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发表时间：
2016
影响因子：
1.7
通讯作者：
Takehiko Mori
中科院分区：
文献类型：
--
作者：
Shohei Kumeta;Tadashi Kawamoto;Takashi Shirahata;Yohji Misaki;Takehiko Mori
研究了新型有机导体(DMEDO-TTF)2X(X=ClO4和BF4)的结构、输运和磁性，其中DMEDO-TTF是二甲基四硫富瓦烯。这些化合物具有完全均匀的堆积结构，表明实现了无二聚间隙的准一维3/4填充带。在冷却过程中，ClO4和BF4盐分别在约190K和210K处表现出一级金属-绝缘体(MI)转变。根据磁化率测量，基态是非磁性绝缘体。低温X射线衍射测量表明，MI转变起源于阴离子有序转变，其超结构波矢与堆积方向相对应；施主均匀堆积结构转变为四聚结构，施主位移较大。四聚体中阴离子向中心两个施主的移动表明绝缘相是电荷密度波态。
The structural, transport, and magnetic properties of the new organic conductors (DMEDO-TTF)2X(X= ClO4and BF4), where DMEDO-TTF is dimethyl(ethylenedioxy)tetrathiafulvalene, have been investigated. These compounds have a complete uniform stack structure, indicating that a quasi-one-dimensional 3/4-filled band without a dimerization gap is realized. The ClO4and BF4salts show a first-order metal–insulator (MI) transition at approximately 190 and 210 K, respectively, in the cooling process. The ground state is a nonmagnetic insulator on the basis of magnetic susceptibility measurements. Low-temperature X-ray diffraction measurements show that the MI transition originates in the anion ordering transition with a superstructure wave vector ofcorresponding to the stacking direction; the uniform donor stacking structure changes to the tetramerized structure with a large shift of the donors. The shift of the anion toward the central two donors in a tetramer indicates that the insulating phase is a charge-density-wave state.