Intertube effects on one-dimensional correlated state of metallic single-wall carbon nanotubes probed by 13C NMR
Intertube effects on one-dimensional correlated state of metallic single-wall carbon nanotubes probed by 13C NMR
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13C NMR探测金属单壁碳纳米管一维相关态的管间效应
DOI：
10.1103/physrevb.95.035128
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Y. Maniwa
中科院分区：
文献类型：
--
作者：
N. Serita;Y. Nakai;K. Matsuda;K. Yanagi;Y. Miyata;T. Saito;Y. Maniwa
孤立单壁碳纳米管（SWCNTs）中的电子态被认为是Tomonaga-Luttinger液体（TLL）的理想实现。然而，目前还不清楚是否一维关联状态下实现的局部环境效应，如形成的束结构。源自束内其他相邻SWCNT的管间效应可显著改变一维关联状态。为了检验TLL模型在成束单壁碳纳米管中的有效性，通过核磁共振（NMR）研究了低能自旋激发。在捆绑的金属和半导体单壁碳纳米管的混合物中的NMR弛豫速率示出了幂律温度依赖性与理论预测的指数。这表明，具有与有效库仑相互作用相同强度的TLL状态在成束样品中实现，如在隔离的SWCNT中。在成束的金属单壁碳纳米管，我们发现一个幂律的弛豫速率的温度依赖性，但弛豫速率的大小是一个数量级小于理论预测。此外，我们发现了一个几乎两倍的大小的Luttinger参数。这些结果表明，抑制自旋激发与减少库仑相互作用成束的金属SWCNT，这是由于管间相互作用源自相邻的金属SWCNT内的束。我们的研究结果提供了直接的证据，捆绑减少了有效的库仑相互作用，通过捆绑金属单壁碳纳米管内的管间相互作用。
The electronic states in isolated single-wall carbon nanotubes (SWCNTs) have been considered as an ideal realization of a Tomonaga-Luttinger liquid (TLL). However, it remains unclear whether one-dimensional correlated states are realized under local environmental effects such as the formation of a bundle structure. Intertube effects originating from other adjacent SWCNTs within a bundle may drastically alter the one-dimensional correlated state. In order to test the validity of the TLL model in bundled SWCNTs, low-energy spin excitation is investigated by nuclear magnetic resonance (NMR). The NMR relaxation rate in bundled mixtures of metallic and semiconducting SWCNTs shows a power-law temperature dependence with a theoretically predicted exponent. This demonstrates that a TLL state with the same strength as that for effective Coulomb interactions is realized in a bundled sample, as in isolated SWCNTs. In bundled metallic SWCNTs, we found a power-law temperature dependence of the relaxation rate, but the magnitude of the relaxation rate is one order of magnitude smaller than that predicted by theory. Furthermore, we found an almost doubled magnitude of the Luttinger parameter. These results indicate suppressed spin excitations with reduced Coulomb interactions in bundled metallic SWCNTs, which are attributable to intertube interactions originating from adjacent metallic SWCNTs within a bundle. Our findings give direct evidence that bundling reduces the effective Coulomb interactions via intertube interactions within bundled metallic SWCNTs.