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(Sb
Bi
)
Te
Ye, M.*; Xu, T.*; Li, G.*; Qiao, S.*; 竹田 幸治; 斎藤 祐児; Zhu, S.-Y.*; Nurmamat, M.*; 角田 一樹*; 石田 行章*; et al.
Physical Review B, 99(14), p.144413_1 - 144413_7, 2019/04
被引用回数：14 パーセンタイル：56.70(Materials Science, Multidisciplinary)We investigate the microscopic origin of ferromagnetism coupled with topological insulators in V-doped (Sb,Bi)
Te employing X-ray magnetic circular dichroism and angle-resolved two-photon photoemission spectroscopies, combined with first-principles calculations. We found an magnetic moment at the Te site anti-parallel to that of the V and Sb sites, which plays a key role in the ferromagnetic order. We ascribe it to the hybridization between Te 5
and V 3
majority spin states at the Fermi energy, consistent with the Zener-type - exchange interaction scenario. The substitution of Bi for Sb suppresses the bulk ferromagnetism by introducing extra electron carriers in the majority spin channel of the Te states that compensates the antiparallel magnetic moment on the Te site. Our findings reveal important clues to designing magnetic topological insulators with higher Curie temperature that work under ambient conditions.
)Lang, R.*; Li, T.*; 松村 大樹; Miao, S.*; Ren, Y.*; Cui, Y.-T.*; Tan, Y.*; Qiao, B.*; Li, L.*; Wang, A.*; et al.
Angewandte Chemie; International Edition, 55(52), p.16054 - 16058, 2016/12
Single-atom catalysts have the advantages of both homogeneous catalysts, such as "isolated sites", and heterogeneous catalysts, such as stability and reusability, and thus would be a promising alternative to traditional homogeneous catalysts. In the hydroformylation of olefins, single-atom Rh catalysts supported on ZnO nanowires demonstrate similar efficiency (TON 
40000) compared to that of homogeneous Wilkinson's catalyst (TON 19000). HAADF-STEM and infrared CO chemisorption experiments identified isolated Rh atoms on the support. XPS and XANES spectra indicate that the electronic state of Rh is almost metallic. The catalysts are about one or two orders of magnitude more active than most reported heterogeneous catalysts and can be reused four times without an obvious decline in activity.
Zr(n,
)
Zr cross section with 
Zr(
O,
O)
Zr reactionsYan, S. Q.*; Li, Z. H.*; Wang, Y. B.*; 西尾 勝久; 牧井 宏之; Su, J.*; Li, Y. J.*; 西中 一朗; 廣瀬 健太郎; Han, Y. L.*; et al.
Physical Review C, 94(1), p.015804_1 - 015804_5, 2016/07
被引用回数：7 パーセンタイル：42.60(Physics, Nuclear)The relative -decay probability ratios of the neutron resonance states in Zr and 
Zr populated via two neutron transfer reactions, Zr(O,O)Zr and 
Zr(O,O)Zr, have been measured to test the validity of the surrogate ratio method (SRM) in determining the (n,) reaction cross section. The cross sections of the Zr(n,)Zr reaction are derived from the experimentally obtained ratios and the cross sections of the 
Zr(n,)Zr reaction in the equivalent neutron energy range of 
= 0 - 8 MeV. The deduced cross sections of Zr(n,)Zr reaction agree with the directly measured ones in the low-energy region, and with the evaluated ENDF/B-VII.1 data at higher energies of 
3 MeV. The agreement supports the concept of the SRM method to indirectly determine the (n,) reaction cross sections.
TeYe, M.*; Li, W.*; Zhu, S.-Y.*; 竹田 幸治; 斎藤 祐児; Wang, J.*; Pan, H.*; Nurmamat, M.*; 角田 一樹*; Ji, F.*; et al.
Nature Communications (Internet), 6, p.8913_1 - 8913_7, 2015/11
被引用回数：58 パーセンタイル：90.37(Multidisciplinary Sciences)磁性元素を添加したトポロジカル絶縁体は、量子異常ホール効果や無散逸伝導などの魅力的な現象の発現が予言され、低消費電力スピンデバイスの開発につながっていくものと期待されている。既に、いくつかの磁性添加トポロジカル絶縁体で長距離磁気秩序が確認されている。しかし、量子異常ホール効果の発現は、極低温におけるCrを添加した(Sb,Bi)Te系に限られており、強磁性の微視的な起源はほとんど分かっていない。そこで、今回、X線磁気円二色性実験による元素選択的研究を行うことにより、本物質系の強磁性は、母体の正孔キャリアーを媒介としたものであり、Crの3d電子とSbやTeのp電子の相互作用が極めて重要であることを明らかにした。この結果は、異常量子ホール素子の実現に向けても重要である。
