Comprehensive transport study of anisotropy and ordering phenomena in quasi-one-dimensional (TMTTF)2X salts (X = PF6,AsF6,SbF6,BF4,ClO4, ReO4)
Comprehensive transport study of anisotropy and ordering phenomena in quasi-one-dimensional (TMTTF)2X salts (X = PF6,AsF6,SbF6,BF4,ClO4, ReO4)
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DOI：
10.1103/physrevb.84.035124
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发表时间：
2011-07-26
影响因子：
3.7
通讯作者：
Dressel, M.
中科院分区：
文献类型：
--
作者：
Koehler, B.;Rose, E.;Dressel, M.
为了研究低温下的各向异性、局部化效应以及电荷 (CO) 和阴离子排序 (AO) 现象，在所有三个晶体方向上测量了准一维有机盐 (TMTTF)(2)X (X = PF6、AsF6、SbF6、BF4、ClO4、ReO4) [四甲基四硫富瓦烯 (TMTTF)] 与温度相关的直流电阻率。对于所有化合物和方向，我们提取不同状态下的传输机制。这些数据经过彻底分析，与结构特性相关，并根据先前的研究和最新理论进行了广泛的讨论。最重要的观察结果是在低于 CO 温度 T-CO 的态密度中出现了一个间隙，这会影响所有三个方向的输运。随着阴离子和硫原子之间的距离减小，该效应变得更强。阴离子和TMTTF堆栈之间的耦合也对AO T-AO处的电阻率异常有严格的影响。在非常低的温度下，激活定律被三维可变范围跳跃所取代。
The temperature-dependent dc resistivity of the quasi-one-dimensional organic salts (TMTTF)(2)X (X = PF6, AsF6, SbF6, BF4, ClO4, ReO4) [tetramethyltetrathiafulvalene (TMTTF)] has been measured in all three crystal directions in order to investigate anisotropy, localization effects, and charge- (CO) and anion-ordering (AO) phenomena at low temperatures. For all compounds and directions, we extract the transport mechanisms in different regimes. The data are thoroughly analyzed, related to structural properties, and extensively discussed in view of previous studies and latest theories. The most important observation is the opening of a gap in the density of states below the CO temperature T-CO that influences the transport in all three directions. The effect becomes stronger as the distance between the anions and the sulfur atoms decreases. The coupling between the anions and the TMTTF stack also has a strict influence on the anomaly in the resistivity at the AO T-AO. At very low temperatures, the activation law is replaced by three-dimensional variable-range hopping.