Theoretical study of anomalous fluctuation and it's effects on dynamical properties of one-dimensional conductors

反常涨落及其对一维导体动力学特性影响的理论研究

• 批准号: 15540343
• 负责人: YOSHIOKA Hideo
• 金额: $ 1.92万
• 依托单位: Nara Women's University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15540343/
• 关键词: molecular conductor; carbon nanotube; nano-graphite ribbon; Mott insulator; charge ordering; Tomonaga-Luttinger liquid; one-dimensional electrons; metal-insulator transition; 充填率1; 4; 核磁気共鳴; 有機導体; 永久電流; 電気伝導; 2; 朝永-ラッティンジャー液体; 光電子分光; スピン励

In collaboration with the experimental group, we directly observed the density of state of carbon nanotubes by the photo emission study. It was shown that Tomonaga-Luttinger liquid state is realized in the carbon nanotubes in the wide range of the temperature from 10 K to room temperature. The nano-graphite ribbons are known to have the anomalous dispersion relation near the Fermi energy different from the usual metals. We investigated the electronic correlation of the materials. It was shown that the mutual interaction leads to Mott insulating ground state and the spin excitation becomes gapless (gapped) for the odd (even) number of zigzag chains.2.Splitting of the Knight shift and of the NMR relaxation rate have been considered to be the experimental evidence of charge ordering in the molecular conductors. In the case of quarter-filling, however, no one show theoretically that the charge ordering leads to such phenomena. In the present study, we calculated the Knight shift and the NM … More R relaxation rate in the pure charge ordered state of one-dimensional extended Hubbard model. Here, the fluctuation around the mean-field solution is taken into account by RPA. It is shown that the both quantities show splitting under the charge ordering, as has been already insisted. In addition, the amount of charge disproportionation estimated from the NMR experiments becomes larger than the actual value.3.Quite recently, the materials with incommensurate decomposition ratios close to 2:1 such as (MDT-TSF)_2X_n, (MDT-ST)_2X_n, and (MDT-TS)_2X_n with X being a monovalent anion and n=0.42〜0.45 have been synthesized and the transport and magnetic properties of these compounds have been measured. The materials (MDT-TSF)_2X_n and (MDT-ST)_2X_n show metallic conduction and undergo the superconducting transition at 4 K for ambient pressure. On the other hand, (MDT-TS)_2(AuI_2)_<0.441> shows the metal-insulator transition at 85 K. In order to clarify why the metal-insulator transition occurs in the case of incommensurate band filling, we investigated the ground state of one-dimensional extended Hubbard model with incommensurate lattices. When the potential from the anions is taken into account, the ground state is Mott insulator, and the increase of band width leads to metal-insulator transition. These results will qualitatively explain the experimental observation shown above. Less

通过与实验组合作，我们通过照片排放研究直接观察了碳纳米管状态的密度。结果表明，在温度从10 K到室温的温度范围内，在碳纳米管中实现了Tomonaga-Luttinger液态。已知纳米环丝带在费米能量附近的异常分散关系与通常的金属不同。我们研究了材料的电子相关性。结果表明，相互的相互作用导致莫特绝缘基态，并且对于奇数（偶数）锯齿形链数的旋转兴奋变得无间隙（间隙）。2。骑士移位和NMR弛豫率的分解被认为是分子导体中电荷有序排序的实验证据。然而，在四分之一填充的情况下，没有人表明收费订购会导致这种现象。在本研究中，我们计算了骑士移位和NM…在一维扩展哈伯德模型的纯电荷有序状态下的更大r弛豫率。在这里，RPA考虑了平均场解决方案周围的波动。结果表明，两个数量都显示在收费排序下分裂，就像已经传输一样。此外，从NMR实验估计的充电量比实际值大。已经测量了这些化合物的合成以及这些化合物的传输和磁性。材料（MDT-TSF）_2X_N和（MDT-ST）_2x_n显示金属传导，并在4 K处进行超导过渡，以实现环境压力。 On the other hand, (MDT-TS)_2(AuI_2)_<0.441> shows the metal-insulator transition at 85 K. In order to clarify why the metal-insulator transition occurs in the case of incommensurate band filling, we investigated the ground state of one-dimensional extended Hubbard model with incommensurate lattices.当考虑到阴离子的电势时，基态是莫特绝缘子，带宽的增加会导致金属 - 绝缘体过渡。这些结果将定性解释上述实验观察。较少的

项目成果

Theoretical Aspects of Charge Ordering in Molecular Conductors

分子导体中电荷排序的理论方面

• 期刊: Journal of the Physical Society of Japan (in press)
• 作者: H.Seo;J.Merino;H.Yoshioka;M.Ogata
• 通讯作者: M.Ogata

Valence-Band Photoemission Study of Single-Wall Carbon Nanotubes

单壁碳纳米管的价带光电研究

• 发表时间: 2003
• 期刊: AIP Conference Proceedings 685
• 作者: H.Shiozawa et al.;(全16名)
• 通讯作者: (全16名)

H.Yoshioka, Y.Hashizume: "Charge ordering and Knight shift in one-dimensional electron systems nearly half-filling"Journal de Physique IV. (印刷中).

H.Yoshioka，Y.Hashizume：“一维电子系统中的电荷排序和奈特位移接近半填充”Journal de Physique IV（出版中）。

Theoretical Study on Knight Shift and Nuclear Spin Relaxation Rate in the Charge Ordering State of the ID Quarter-filled Electron System

ID 1/4填充电子系统电荷有序态下奈特位移和核自旋弛豫率的理论研究

• 期刊: Journal of Low Temperature Physics (印刷中)
• 作者: H.Yoshioka;H.Hashizume;H.Yoshioka;H.Shiozawa et al.;H.Yoshioka;H.Ishii et al.;H.Yoshioka
• 通讯作者: H.Yoshioka

H.Yoshioka, Y.Hashizume: "Excitations in the charge ordered state of one-dimensional extended Hubbard model at half-filling"Synthetic Metals. 135-136. 551-552 (2003)

H.Yoshioka，Y.Hashizume：“半填充时一维扩展哈伯德模型的电荷有序态激发”合成金属。