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Entani, Shiro; Antipina, L. Y.*; Avramov, P.*; Otomo, Manabu*; Matsumoto, Yoshihiro*; Hirao, Norie; Shimoyama, Iwao; Naramoto, Hiroshi*; Baba, Yuji; Sorokin, P. B.*; et al.
Nano Research, 8(5), p.1535 - 1545, 2015/05
Times Cited Count:28 Percentile:71.13(Chemistry, Physical)Avramov, P. V.*; Kuzubov, A. A.*; Sakai, Seiji; Otomo, Manabu*; Entani, Shiro; Matsumoto, Yoshihiro*; Eleseeva, N. S.*; Pomogaev, V. A.*; Naramoto, Hiroshi*
Journal of Porphyrins and Phthalocyanines, 18(7), p.552 - 568, 2014/07
Times Cited Count:1 Percentile:4.96(Chemistry, Multidisciplinary)Otomo, Manabu; Yamauchi, Yasushi*; Kuzubov, A. A.*; Eliseeva, N. S.*; Avramov, P.*; Entani, Shiro; Matsumoto, Yoshihiro; Naramoto, Hiroshi*; Sakai, Seiji
Applied Physics Letters, 104(5), p.051604_1 - 051604_4, 2014/02
Times Cited Count:12 Percentile:44.87(Physics, Applied)Hexagonal boron nitride (h-BN) is a promising barrier material for graphene spintronics. In this study, spin-polarized metastable de-excitation spectroscopy (SPMDS) is employed to study the spin-dependent electronic structure of monolayer h-BN on Ni(111). The extreme surface sensitivity of SPMDS enables us to elucidate a partial filling of the in-gap states of h-BN without any superposition of Ni 3 signals. The in-gap states are shown to have a considerable spin polarization parallel to the majority spin of Ni. The positive spin polarization is attributed to the
-
hybridization and the effective spin transfer to the nitrogen atoms at the h-BN/Ni(111) interface.
Matsumoto, Yoshihiro; Entani, Shiro; Koide, Akihiro*; Otomo, Manabu; Avramov, P.; Naramoto, Hiroshi*; Amemiya, Kenta*; Fujikawa, Takashi*; Sakai, Seiji
Journal of Materials Chemistry C, 1(35), p.5533 - 5537, 2013/09
Times Cited Count:34 Percentile:76.08(Materials Science, Multidisciplinary)Otomo, Manabu; Tsuchida, Yuya*; Muraya, Naoki*; Yanase, Takashi*; Sakai, Seiji; Yonezawa, Tetsu*; Nagahama, Taro*; Hasegawa, Tetsuya*; Shimada, Toshihiro*
Journal of Physical Chemistry C, 117(22), p.11555 - 11561, 2013/06
Times Cited Count:2 Percentile:8.32(Chemistry, Physical)We report in-plane orientation control of newly developed high-mobility organic semiconductor: 2,7-diphenyl[1]benzothieno[3,2-][1]benzothiophene (DPh-BTBT). As previously reported on monolayer pentacene, it was revealed that bunched steps on vicinal Si(111) with bismuth termination break the surface symmetry and reduce three-fold symmetry of DPh-BTBT grains into quasi-single orientation. Interestingly, the critical step height necessary for the orientation control was different from that of pentacene. We examined several mechanisms of orientation control and concluded that the facet nano structure fabricated by step bunching is working as an anisotropic template. We will also show the wettability control of bismuth terminated silicon surface and show that the growth mode of DPh-BTBT is dependent on the surface nanostructure of Bi-Si.
Sakai, Seiji; Matsumoto, Yoshihiro; Otomo, Manabu; Entani, Shiro; Avramov, P.; Sorokin, P. B.*; Naramoto, Hiroshi*
Synthetic Metals, 173, p.22 - 25, 2013/06
Times Cited Count:3 Percentile:14.29(Materials Science, Multidisciplinary)Avramov, P.; Kuzubov, A. A.*; Sakai, Seiji; Otomo, Manabu; Entani, Shiro; Matsumoto, Yoshihiro; Naramoto, Hiroshi*; Eliseeva, N. S.*
Journal of Applied Physics, 112(11), p.114303_1 - 114303_10, 2012/12
Times Cited Count:18 Percentile:57.64(Physics, Applied)Avramov, P.; Fedorov, D. G.*; Sorokin, P. B.*; Sakai, Seiji; Entani, Shiro; Otomo, Manabu; Matsumoto, Yoshihiro; Naramoto, Hiroshi*
Journal of Physical Chemistry Letters (Internet), 3(15), p.2003 - 2008, 2012/08
Times Cited Count:38 Percentile:79.31(Chemistry, Physical)Antipina, L. Y.*; Avramov, P.; Sakai, Seiji; Naramoto, Hiroshi*; Otomo, Manabu; Entani, Shiro; Matsumoto, Yoshihiro; Sorokin, P. B.*
Physical Review B, 86(8), p.085435_1 - 085435_7, 2012/08
Times Cited Count:55 Percentile:86.45(Materials Science, Multidisciplinary)Sakai, Seiji; Mitani, Seiji*; Matsumoto, Yoshihiro; Entani, Shiro; Avramov, P.; Otomo, Manabu; Naramoto, Hiroshi*; Takanashi, Koki
Journal of Magnetism and Magnetic Materials, 324(12), p.1970 - 1974, 2012/06
Times Cited Count:3 Percentile:13.88(Materials Science, Multidisciplinary)Entani, Shiro; Matsumoto, Yoshihiro; Otomo, Manabu; Avramov, P.; Naramoto, Hiroshi*; Sakai, Seiji
Journal of Applied Physics, 111(6), p.064324_1 - 064324_6, 2012/03
Times Cited Count:21 Percentile:62.48(Physics, Applied) analysis was performed on the graphene growth in ultrahigh vacuum chemical vapor deposition by exposing the epitaxial Ni(111) thin film to benzene vapor at 873 K. It is shown that the highly uniform single- and bi-layer graphenes can be synthesized by the control of benzene exposure in the range of 10-10
langmuirs, reflecting a change in the graphene growth-rate by three orders of magnitude in between the first and second layer. Electron energy loss spectroscopy measurements of single- and bi-layer graphenes indicates that the interface interaction between bi-layer graphene and Ni(111) is weakened in comparison with that between single-layer graphene and Ni(111). It is also clarified from the micro-Raman analysis that the structural and electrical uniformities of the graphene film transformed on a SiO
substrate are improved remarkably under the specific exposure conditions at which the growths of single- and bi-layer graphenes are completed.
Sakai, Seiji; Mitani, Seiji*; Matsumoto, Yoshihiro; Otomo, Manabu; Entani, Shiro; Avramov, P.; Naramoto, Hiroshi*; Fujikawa, Takashi*
no journal, ,
Entani, Shiro; Matsumoto, Yoshihiro; Otomo, Manabu; Avramov, P.; Naramoto, Hiroshi*; Sakai, Seiji
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Matsumoto, Yoshihiro; Entani, Shiro; Otomo, Manabu; Avramov, P.; Naramoto, Hiroshi*; Amemiya, Kenta*; Sakai, Seiji
no journal, ,
Avramov, P.; Sakai, Seiji; Entani, Shiro; Matsumoto, Yoshihiro; Otomo, Manabu; Kuzukov, A.*; Naramoto, Hiroshi*
no journal, ,
The atomic and electronic structures and spin states of helium and nickel nanocusters on metallic armchair graphene nanoribbons were studied using ab initio PBC/HSE technique. To reproduce the electronic and band structure of graphene, quasi-metallic armchair nanoribbons of different width and length with 0.05-0.15 eV band gaps were used as structural models. To study the mechanisms of clusterization of helium and nickel atoms on graphene, the potential energy surfaces of He and Ni migration were calculated using elastic membrane and absolutely rigid substrate approximations. It was found that the eta 6 coordination of He and Ni atoms is the only one energetically favorable position of the absorbed single atoms on graphene. The potential energy barriers of dissociation, regrouping and clusterization of the atoms were calculated.
Sakai, Seiji; Matsumoto, Yoshihiro; Otomo, Manabu; Entani, Shiro; Avramov, P.; Naramoto, Hiroshi*; Takagi, Yasumasa*; Nakagawa, Takeshi*; Yokoyama, Toshihiko*
no journal, ,
no abstracts in English
Entani, Shiro; Matsumoto, Yoshihiro; Otomo, Manabu; Avramov, P.; Naramoto, Hiroshi*; Sakai, Seiji
no journal, ,
no abstracts in English
Matsumoto, Yoshihiro; Entani, Shiro; Otomo, Manabu; Avramov, P.; Naramoto, Hiroshi*; Amemiya, Kenta*; Sakai, Seiji
no journal, ,
In the present study, the electronic and magnetic states of the graphene/FM interface are investigated for the single-layer graphene (SLG)/Ni(111) and bilayer graphene (BLG)/Ni(111) structures by using the depth-resolved X-ray magnetic circular dichroism (XMCD) spectroscopy. For the SLG/Ni(111) structure, an intense XMCD signal was observed in the C K-edge XMCD spectrum measured by reversing the remanent magnetization of Ni(111). This indicates that spin polarization is induced in the -orbitals of SLG by the contact with Ni(111) even at room temperature. More interestingly, the BLG/Ni(111) structure is found to show the C K-edge XMCD signal whose intensity changes dramatically with the probing depth. On the other hand, the depth-resolved analysis of the Ni L-edge XMCD spectrum demonstrated that the magnetization of Ni decreases by 20-30 % within a few atomic layers from the graphene (SLG, BLG)/Ni(111) interfaces, possibly associated with the formation of C-Ni bonds.
Entani, Shiro; Matsumoto, Yoshihiro; Otomo, Manabu; Avramov, P.; Naramoto, Hiroshi*; Sakai, Seiji
no journal, ,
no abstracts in English
Matsumoto, Yoshihiro; Entani, Shiro; Otomo, Manabu; Avramov, P.; Naramoto, Hiroshi*; Amemiya, Kenta*; Sakai, Seiji
no journal, ,
no abstracts in English