ELECTRICAL-CONDUCTIVITY, THERMOELECTRIC-POWER, AND ELECTRON-SPIN-RESONANCE OF A NEW FAMILY OF MOLECULAR CONDUCTORS, DICYANOQUINONEDIIMINE-METAL [(DCNQI)2M] COMPOUNDS
ELECTRICAL-CONDUCTIVITY, THERMOELECTRIC-POWER, AND ELECTRON-SPIN-RESONANCE OF A NEW FAMILY OF MOLECULAR CONDUCTORS, DICYANOQUINONEDIIMINE-METAL [(DCNQI)2M] COMPOUNDS
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DOI：
10.1103/physrevb.38.5913
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发表时间：
1988-09-15
影响因子：
3.7
通讯作者：
KOBAYASHI, H
中科院分区：
文献类型：
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作者：
MORI, T;INOKUCHI, H;KOBAYASHI, H
2-R1 -5-R2-DCNQI（R1，R2 = CH 3，CH 3 O，Cl，Br; DCNQI= N，N '-二氰基醌二亚胺）是一类新的有机分子，它既能作为配体又能作为电子受体形成高导电、电荷转移和配位化合物（2-R1 -5-R2-DCNQI）2 M（M= Cu，Ag，Li，Na，K，NH 4）.通过测量电导率、热电功率和电子自旋共振来研究这些盐，通过将它们分为三组来适当地理解它们。I族DCNQI盐由具有除Cu以外的阳离子M的盐组成，在50和100 K之间经历Peierls转变。它们的热电势由Hubbard模型的大U极限解释。第II族DCNQI盐，即卤素取代的DCNQI的Cu盐，也在150和250 K之间表现出Peierls转变，随后在10 K附近出现反铁磁转变。在一维紧束缚近似下，带宽估计为0.4-0.5 eV。第三族DCNQI盐中，R1 = R2 = CH 3或CH 3 O的铜盐在低至1.5K时仍保持金属导电性，而在5.5K时发生磁转变。这可能是第一种金属导电和磁序共存的有机导体。磁序归因于相对局部化的Cu 2+自旋，其独立于DCNQI上的传导电子，其中Cu的平均氧化态估计为Cu 1。3+.. AE
A new family of organic molecules, 2-R 1-5-R 2-DCNQI (with R 1, R 2= CH 3, CH 3 O, Cl, or Br; DCNQI= N, N’-dicyanoquinonediimine) works as a ligand as well as an electron acceptor to form highly conducting, charge-transfer and coordination compounds as (2-R 1-5-R 2-DCNQI) 2 M (with M= Cu, Ag, Li, Na, K, or NH 4). These salts are investigated by the measurements of electrical conductivity, thermoelectric power, and electron spin resonance, which are appropriately understood by classifying them into three groups. Group-I DCNQI salts consisting of the salts with cations M other than Cu, undergo the Peierls transitions between 50 and 100 K. Their thermoelectric power is interpreted by the large-U limit of the Hubbard model. Group-II DCNQI salts, the Cu salts of the halogen-substituted DCNQI, also exhibit the Peierls transitions between 150 and 250 K, followed by the antiferromagnetic transitions around 10 K. With the one-dimensional tight-binding approximation, the bandwidth is estimated to be 0.4–0.5 eV. Group-III DCNQI salts, the Cu salts with R 1= R 2= CH 3 or CH 3 O retain metallic conductivity down to 1.5 K, whereas a magnetic transition takes place at 5.5 K. This may be the first organic conductor in which metallic conduction and a magnetic order coexist. The magnetic order is attributed to the comparatively localized Cu 2+ spins present independently of the conduction electrons on DCNQI, where the average oxidation state of Cu has been estimated to be Cu 1. 3+.. AE