Novel Electronic Properties of a Nano-Graphite Disordered Network and Their Iodine Doping Effects.
Novel Electronic Properties of a Nano-Graphite Disordered Network and Their Iodine Doping Effects.
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纳米石墨无序网络的新电子特性及其碘掺杂效应。
DOI：
10.1143/jpsj.69.754
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发表时间：
2000
影响因子：
1.7
通讯作者：
M. Endo
中科院分区：
文献类型：
--
作者：
Y. Shibayama;H. Sato;T. Enoki;X. Bi;M. Dresselhaus;M. Endo
活性炭纤维（ACF）是由纳米石墨的三维无序网络组成的微孔碳，其平均面内尺寸为约30 A。研究了2800° C热处理ACF样品的结构、电子性质和碘掺杂效应。低于1000° C热处理的样品表现出库仑能隙变程跳跃导电和局部自旋的存在，表明纳米石墨中的充电效应和边缘继承的非成键态的重要性，后者是理论预测的。碘掺杂降低了充电效应，这是由于介电常数被容纳在微孔中的碘增强。1300° C以上的热处理使活性碳纤维从安德森绝缘体转变为无序金属，形成了无限的纳米石墨间电子输运渗透路径网络，并伴随着从局域自旋磁性到巡回电子磁性的转变。在金属制度，载体SC…
Activated carbon fibers (ACFs) are microporous carbons consisting of a three-dimensional disordered network of nano-graphites with a mean in-plane size of about 30 A. We investigated the structure, electronic properties and iodine doping effects for ACF samples heat-treated up to 2800° C. The samples heat-treated below 1000° C exhibit Coulomb gap variable-range hopping conduction and the presence of localized spins, suggesting the importance of charging effects and the edge-inherited non-bonding states in nano-graphites, the latter being predicted theoretically. Iodine doping reduces the charging effect due to the dielectric constant enhanced by the iodine that is accommodated in the micropores. Heat treatment above 1300° C changes ACFs from an Anderson insulator to a disordered metal by the development of an infinite inter-nano-graphite percolation path network for electron transport, accompanied by a change from localized-spin magnetism to itinerant electron magnetism. In the metallic regime, carrier sc...