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2. Intertube effects on one-dimensional correlated state of metallic single-wall carbon nanotubes probed by 13C NMR

Author

Serita, Noboru, Nakai, Yusuke, Matsuda, Kazuyuki, Yanagi, Kazuhiro, Miyata, Yasumitsu, Saito, Takeshi, and Maniwa, Yutaka

Subjects
Condensed Matter - Strongly Correlated Electrons, Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

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., Comment: 6 pages, 3 figures

Published
2017
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3. Observation of the intrinsic magnetic susceptibility of highly purified single-wall carbon nanotubes

Author

Nakai, Yusuke, Tsukada, Ryo, Miyata, Yasumitsu, Saito, Takeshi, Hata, Kenji, and Maniwa, Yutaka

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Strongly Correlated Electrons
Abstract

We report the observation of the intrinsic magnetic susceptibility of highly purified SWCNT samples prepared by a combination of acid treatment and density gradient ultracentrifugation (DGU). We observed that the diamagnetic susceptibility of SWCNTs increases linearly with increasing nanotube diameter. We found that the magnetic susceptibility divided by the diameter is a universal function of the scaled temperature. Furthermore, the estimated magnetic susceptibilities of pure semiconducting and pure metallic SWCNT samples suggest that they respond differently to changes in carrier density, which is consistent with theory. These findings provide experimental verification of the theoretically predicted diameter, temperature, and metallicity dependence of the magnetic susceptibility., Comment: 5 pages

Published
2015
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5. Giant Seebeck coefficient in semiconducting single-wall carbon nanotube film

Author

Nakai, Yusuke, Honda, Kazuya, Yanagi, Kazuhiro, Kataura, Hiromichi, Kato, Teppei, Yamamoto, Takahiro, and Maniwa, Yutaka

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Materials Science
Abstract

We found a giant Seebeck effect in semiconducting single-wall carbon nanotube (SWCNT) films, which exhibited a performance comparable to that of commercial Bi2Te3 alloys. Carrier doping of semiconducting SWCNT films further improved the thermoelectric performance. These results were reproduced well by first-principles transport simulations based on a simple SWCNT junction model. These findings suggest strategies that pave the way for emerging printed, all-carbon, flexible thermoelectric devices., Comment: 16 pages, 5 figures

Published
2014
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6. Rietveld analysis and maximum entropy method of powder diffraction for bundles of single-walled carbon nanotubes

Author

Kadowaki, Hiroaki, Nishiyama, Akihito, Matsuda, Kazuyuki, Maniwa, Yutaka, Suzuki, Shinzo, Achiba, Yohji, and Kataura, Hiromichi

Subjects
Condensed Matter - Materials Science
Abstract

The structure of bundles of single-walled carbon nanotubes (SWNT) has been refined by Rietveld analysis using neutron and X-ray powder diffraction data. Based on previous simulation studies of powder diffraction data of SWNT and standard Rietveld analyses, we have developed a pattern fit technique for SWNT which provides precise structure parameters. We also show that the present technique can be used with the maximum entropy method (MEM), which is complementary to the Rietveld analysis. Using the neutron diffraction data of pristine SWNT, we have successfully reconstructed the density of carbon nuclei and zero density in the inner cavity of SWNT by MEM., Comment: 7 pages, 3 figures

Published
2004
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13. Superconductivity in alkali-metal-doped picene

Author

Mitsuhashi, Ryoji, Suzuki, Yuta, Yamanari, Yusuke, Mitamura, Hiroki, Kambe, Takashi, Ikeda, Naoshi, Okamoto, Hideki, Fujiwara, Akihiko, Yamaji, Minoru, Kawasaki, Naoko, Maniwa, Yutaka, and Kubozono, Yoshihiro

Subjects
Thin films -- Magnetic properties -- Analysis, Crystals -- Structure, Clathrate compounds -- Magnetic properties -- Analysis, Electrical conductivity -- Analysis, Hydrocarbons -- Magnetic properties -- Analysis, Dielectric films -- Magnetic properties -- Analysis, Superconductors -- Magnetic properties -- Analysis, Boron nitride -- Magnetic properties -- Analysis, Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

Efforts to identify and develop new superconducting materials continue apace, motivated by both fundamental science and the prospects for application. For example, several new superconducting material systems have been developed in the recent past, including calcium-intercalated graphite compounds (1), boron-doped diamond (2) and-most prominently-iron arsenides such as [LaO.sub.1-x][F.sub.x]FeAs (ref. 3). In the case of organic superconductors, however, no new material system with a high superconducting transition temperature ([T.sub.c]) has been discovered in the past decade. Here we report that intercalating an alkali metal into picene, a wide-bandgap semiconducting solid hydrocarbon, produces metallic behaviour and superconductivity. Solid potassium-intercalated picene ([K.sub.x]picene) shows [T.sub.c] values of 7K and 18 K, depending on the metal content. The drop of magnetization in [K.sub.x]picene solids at the transition temperature is sharp (, The metal doping of organic molecular compounds and graphites, solids with p-electron networks, has been extensively studied in the search for novel physical properties, such as metallic behaviour and superconductivity [...]

Published
2010
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14. Photosensitive function of encapsulated dye in carbon nanotubes

Author

Yanagi, Kazuhiro, Iakoubovskii, Konstantin, Matsui, Hiroyuki, Matsuzaki, Hiroyuki, Okamoto, Hiroshi, Miyata, Yasumitsu, Maniwa, Yutaka, Kazaoui, Said, Minami, Nobutsugu, and Kataura, Hiromichi

Subjects
Protein folding -- Research, Nanotubes -- Structure, Nanotubes -- Chemical properties, Polypeptides -- Structure, Polypeptides -- Chemical properties, Chemistry
Abstract

The microscopic structure and photosensitive function of encapsulated dye in the single-wall carbon nanotubes (SWCNTs) are studied. The findings suggest that the photoexcitation of such dyes leads to the enhancement of transient absorption saturation in the nanotubes, which also proves the transfer of ultrafast energy from the dye to SWCNTs.

Published
2007

22. Magnetic Properties of One- and Two-Dimensional Functional Materials: Oxygen Molecules Encapsulated in Single-Walled Carbon Nanotubes and Copper Ions Embedded into Phthalocyanine Sheets

Author

Hagiwara, Masayuki, primary, Kida, Takanori, additional, Matsuda, Kazuyuki, additional, Kyakuno, Haruka, additional, Maniwa, Yutaka, additional, Honda, Zentaro, additional, Sakaguchi, Yuya, additional, Tashiro, Makoto, additional, Sakai, Masamichi, additional, Fukuda, Takeshi, additional, Kamata, Norihiko, additional, and Okunishi, Kouichi, additional

Published
2019
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24. Restoring the intrinsic optical properties of CVD-grown MoS2 monolayers and their heterostructures

Author

Kojima, Kana, primary, Lim, Hong En, additional, Liu, Zheng, additional, Zhang, Wenjin, additional, Saito, Tetsuki, additional, Nakanishi, Yusuke, additional, Endo, Takahiko, additional, Kobayashi, Yu, additional, Watanabe, Kenji, additional, Taniguchi, Takashi, additional, Matsuda, Kazunari, additional, Maniwa, Yutaka, additional, Miyauchi, Yuhei, additional, and Miyata, Yasumitsu, additional

Published
2019
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25. Monolayer MoS2 growth at the Au–SiO2 interface

Author

Lim, Hong En, primary, Irisawa, Toshifumi, additional, Okada, Naoya, additional, Okada, Mitsuhiro, additional, Endo, Takahiko, additional, Nakanishi, Yusuke, additional, Maniwa, Yutaka, additional, and Miyata, Yasumitsu, additional

Published
2019
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28. Regulated Single‐Axis Rotations of a Carbonaceous Guest in a van der Waals Complex with an Entropy Cost.

Author

Matsuno, Taisuke, Nakai, Yusuke, Maniwa, Yutaka, Someya, Maki, Sato, Sota, and Isobe, Hiroyuki

Subjects
VAN der Waals forces, ROTATIONAL motion
Abstract

In a tight host–guest complex assembled solely by nondirectional van der Waals forces, unique motions of the guest, such as solid‐state inertial rotations, emerge. The regulation of dynamic motions is an important element to be explored for novel functions of such complexes, which may be seemingly difficult to achieve because of the nondirectionality of the assembling forces. A regulated, single‐axis rotation was made possible by choosing an appropriate shape of the guest in the tubular host. Specifically, an ellipsoidal guest was made to stand along a cylinder axis of the host, which consequently resulted in single‐axis rotations of the guest in the solid. The rotational frequency was considerably high for solid‐state rotations but was suppressed to 10 GHz, which was 1/20 of the isotropic rotation of a spherical guest. In‐depth kinetic analyses quantitatively revealed that the entropy cost was a determining factor that regulated the dynamics. [ABSTRACT FROM AUTHOR]

Published
2020
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30. Confined water inside single-walled carbon nanotubes: Global phase diagram and effect of finite length.

Author

Kyakuno, Haruka, Matsuda, Kazuyuki, Yahiro, Hitomi, Inami, Yu, Fukuoka, Tomoko, Miyata, Yasumitsu, Yanagi, Kazuhiro, Maniwa, Yutaka, Kataura, Hiromichi, Saito, Takeshi, Yumura, Motoo, and Iijima, Sumio

Subjects
CARBON nanotubes, WATER, PHASE diagrams, X-ray diffraction, PHASE transitions, NUCLEAR magnetic resonance, TRANSITION temperature, MOLECULAR dynamics
Abstract

Studies on confined water are important not only from the viewpoint of scientific interest but also for the development of new nanoscale devices. In this work, we aimed to clarify the properties of confined water in the cylindrical pores of single-walled carbon nanotubes (SWCNTs) that had diameters in the range of 1.46 to 2.40 nm. A combination of x-ray diffraction (XRD), nuclear magnetic resonance, and electrical resistance measurements revealed that water inside SWCNTs with diameters between 1.68 and 2.40 nm undergoes a wet-dry type transition with the lowering of temperature; below the transition temperature Twd, water was ejected from the SWCNTs. Twd increased with increasing SWCNT diameter D. For the SWCNTs with D = 1.68, 2.00, 2.18, and 2.40 nm, Twd obtained by the XRD measurements were 218, 225, 236, and 237 K, respectively. We performed a systematic study on finite length SWCNT systems using classical molecular dynamics calculations to clarify the effect of open ends of the SWCNTs and water content on the water structure. It was found that ice structures that were formed at low temperatures were strongly affected by the bore diameter, a = D - σOC, where σOC is gap distance between the SWCNT and oxygen atom in water, and the number of water molecules in the system. In small pores (a < 1.02 nm), tubule ices or the so-called ice nanotubes (ice NTs) were formed irrespective of the water content. On the other hand, in larger pores (a > 1.10 nm) with small water content, filled water clusters were formed leaving some empty space in the SWCNT pore, which grew to fill the pore with increasing water content. For pores with sizes in between these two regimes (1.02 < a < 1.10 nm), tubule ice also appeared with small water content and grew with increasing water content. However, once the tubule ice filled the entire SWCNT pore, further increase in the water content resulted in encapsulation of the additional water molecules inside the tubule ice. Corresponding XRD measurements on SWCNTs with a mean diameter of 1.46 nm strongly suggested the presence of such a filled structure. [ABSTRACT FROM AUTHOR]

Published
2011
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31. Selective oxidation of semiconducting single-wall carbon nanotubes by hydrogen peroxide

Author

Miyata, Yasumitsu, Maniwa, Yutaka, and Kataura, Hiromichi

Subjects
Hydrogen peroxide -- Chemical properties, Nanotubes -- Chemical properties, Oxidation-reduction reaction -- Analysis, Chemicals, plastics and rubber industries
Abstract

Selective oxidation of single-wall carbon nanotubes (SWCNTs) by H2O2 was conducted at varying heating times. This process was monitored by UV-vis-NIR spectroscopy resulting in a major increase in the relative absorption intensity that indicated a higher than 80% concentration of metallic SWCNTs in the final product.

Published
2006

40. C_<70> Molecular Stumbling inside Single-Walled Carbon Nanotubes

Author

Maniwa, Yutaka, Kataura, Hiromichi, Abe, Masatoshi, Fujiwara, Akihiko, Fujiwara, Ryuji, Kira, Hiroshi, Tou, Hideki, Suzuki, Shinzo, Achiba, Yohji, Nishibori, Eiji, Takata, Masaki, Sakata, Makoto, and Suematsu, Hiroyoshi

Subjects
peapod, phase transition, XRD, fullerene, SWNT, structure, carbon nanotube, %22">C_<70>, thermal expansion
Abstract

We report the structural study of C_-one-dimensional (1D) crystal formed inside single-walled carbon nanotubes (SWNTs). X-ray diffraction measurements were performed between 100 K and 999 K on C_-encapsulated SWNTs with an average diameter of 1.37 nm. Two different domains, where the dominant alignment of C_ molecular long axis is standing or lying with respect to the tube axis, were observed; the ratio of the standing to the lying C_-domains is roughly 7:3. Thermal expansion of interfullerene distance gave no evidence for orientational phase transitions, not as in the 3D crystals. Instead, the long-range order of the standing C_-alignment was thermally destroyed with an activation energy of 39±4 meV. The results imply the importance of either the 1D fluctuation or the tube-C_ interaction at finite temperatures.

Published
2003

44. Modulation of electrical potential and conductivity in an atomic-layer semiconductor heterojunction

Author

Kobayashi, Yu, primary, Yoshida, Shoji, additional, Sakurada, Ryuji, additional, Takashima, Kengo, additional, Yamamoto, Takahiro, additional, Saito, Tetsuki, additional, Konabe, Satoru, additional, Taniguchi, Takashi, additional, Watanabe, Kenji, additional, Maniwa, Yutaka, additional, Takeuchi, Osamu, additional, Shigekawa, Hidemi, additional, and Miyata, Yasumitsu, additional

Published
2016
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50. NMR study in the superconducting silicon clathrate compound NaxBaySi46

Author

Shimizu, Fumihiko, Maniwa, Yutaka, Kume, Kiyoshi, Kawaji, Hitoshi, Yamanaka, Shoji, and Ishikawa, Mitsuo

Abstract

29Si, 23Na, 137Ba, and 135Ba NMR experiments were carried out in the superconducting silicon clathrate compound NaxBaySi46 to study the electronic states above the superconducting transition temperature. We observed three distinct 29Si signals with different Knight shift (2036, 862, and 720 ppm at 90 K with a small temperature dependence of ∼10%), which were ascribed to inequivalent Si sites in the Si46 structure. The results indicate that the conduction-electron spin and/or charge density is strongly site-dependent. At all the atomic sites, the Korringa relation in NMR relaxation was observed, indicative of metallic electronic structure with moderate electronic correlation. The Na and Ba atoms are partially ionized in NaxBaySi46, which shows the noticeable difference from the system of alkali-metal-doped fullerides. The comparison with band calculations is discussed.

Published
1996

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