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FeSiSumida, Kazuki; Fujita, Yuichi*; Zhou, W.*; Masuda, Keisuke*; Kawasaki, Ikuto; Fujimori, Shinichi; Kimura, Akio*; Sakuraba, Yuya*
Physical Review B, 108(24), p.L241101_1 - L241101_6, 2023/12
states in the electronic structure of the intermediate-valence superconductor CeIr
Fujimori, Shinichi; Kawasaki, Ikuto; Takeda, Yukiharu; Yamagami, Hiroshi; Sasabe, Norimasa*; Sato, Yoshiki*; Shimizu, Yusei*; Nakamura, Ai*; Maruya, A.*; Homma, Yoshiya*; et al.
Electronic Structure (Internet), 5(4), p.045009_1 - 045009_7, 2023/11
Kawasaki, Ikuto; Takeuchi, Kazuharu*; Fujimori, Shinichi; Takeda, Yukiharu; Yamagami, Hiroshi; Yamamoto, Etsuji; Haga, Yoshinori
Physical Review B, 108(16), p.165127_1 - 165127_9, 2023/10
localized ferromagnet CeRuGe studied by soft X-ray photoemission spectroscopyKawasaki, Ikuto; Fujimori, Shinichi; Takeda, Yukiharu; Yamagami, Hiroshi; Onuki, Yoshichika*
Journal of the Physical Society of Japan, 92(6), p.064709_1 - 064709_8, 2023/06
Rh
Sn
Iwasa, Kazuaki*; Suyama, Kazuya*; Kawamura, Seiko; Nakajima, Kenji; Raymond, S.*; Steffens, P.*; Yamada, Akira*; Matsuda, Tatsuma*; Aoki, Yuji*; Kawasaki, Ikuto; et al.
Physical Review Materials (Internet), 7(1), p.014201_1 - 014201_11, 2023/01
Times Cited Count：2 Percentile：62.48(Materials Science, Multidisciplinary)P studied by soft X-ray photoemission spectroscopyKawasaki, Ikuto; Kobata, Masaaki; Fujimori, Shinichi; Takeda, Yukiharu; Yamagami, Hiroshi; Hedo, Masato*; Nakama, Takao*; Onuki, Yoshichika*
Physical Review B, 104(16), p.165124_1 - 165124_8, 2021/10
Times Cited Count：0 Percentile：0(Materials Science, Multidisciplinary)
Fujimori, Shinichi; Kawasaki, Ikuto; Takeda, Yukiharu; Yamagami, Hiroshi; Nakamura, Ai*; Homma, Yoshiya*; Aoki, Dai*
Journal of the Physical Society of Japan, 90(1), p.015002_1 - 015002_2, 2021/01
Times Cited Count：13 Percentile：79.65(Physics, Multidisciplinary) studied by soft X-ray angle-resolved photoemission spectroscopyKawasaki, Ikuto; Kobata, Masaaki; Fujimori, Shinichi; Takeda, Yukiharu; Yamagami, Hiroshi; Nakamura, Ai*; Iha, Wataru*; Hedo, Masato*; Nakama, Takao*; Onuki, Yoshichika*
Journal of the Physical Society of Japan, 89(4), p.044704_1 - 044704_6, 2020/04
Times Cited Count：3 Percentile：30.12(Physics, Multidisciplinary)Fe
O
Kobata, Masaaki; Yoshii, Kenji; Fukuda, Tatsuo; Kawasaki, Ikuto; Okane, Tetsuo; Yamagami, Hiroshi; Yaita, Tsuyoshi; Harii, Kazuya; Ieda, Junichi; Okayasu, Satoru; et al.
JPS Conference Proceedings (Internet), 30, p.011192_1 - 011192_6, 2020/03
High energy X-ray photoelectron spectroscopy (HAXPES) measurements were carried out for the Spin Seebeck system Pt/YFeO(YIG). This system was found to show anomalous Hall effect, possible due to the formation of intermetallic compounds between Fe
and Pt. To reveal this possibility, we have measured the Fe 1s photoelectron peaks by using HAXPES. It was found that the Fe ions consist of Fe in YIG and metallic Fe. The formation of the metallic state is consistent with the proposed origin of the anomalous Hall effect. Other spectra such as Pt 4f will be presented at the conference.
studied by photoelectron spectroscopyFujimori, Shinichi; Kawasaki, Ikuto; Takeda, Yukiharu; Yamagami, Hiroshi; Nakamura, Ai*; Homma, Yoshiya*; Aoki, Dai*
Journal of the Physical Society of Japan, 88(10), p.103701_1 - 103701_5, 2019/10
Times Cited Count：31 Percentile：86.81(Physics, Multidisciplinary)Ge and EuCuSi studied by soft X-ray photoemission spectroscopyKawasaki, Ikuto; Fujimori, Shinichi; Takeda, Yukiharu; Yamagami, Hiroshi; Iha, Wataru*; Hedo, Masato*; Nakama, Takao*; Onuki, Yoshichika*
Physical Review B, 100(3), p.035111_1 - 035111_8, 2019/07
Times Cited Count：8 Percentile：40.86(Materials Science, Multidisciplinary)TiBi
Motoyama, Gaku*; Haga, Yoshinori; Yamaguchi, Akira*; Kawasaki, Ikuto*; Sumiyama, Akihiko*; Yamamura, Tomoo*
Progress in Nuclear Science and Technology (Internet), 5, p.157 - 160, 2018/11
La
RuO studied by soft X-ray photoemission spectroscopyKawasaki, Ikuto*; Sakon, Yumi*; Fujimori, Shinichi; Yamagami, Hiroshi; Tenya, Kenichi*; Yokoyama, Makoto*
Physical Review B, 94(17), p.174427_1 - 174427_7, 2016/11
Times Cited Count：5 Percentile：25.63(Materials Science, Multidisciplinary) and UCoGe studied by angle-resolved photoelectron spectroscopyFujimori, Shinichi; Okochi, Takuo*; Kawasaki, Ikuto*; Yasui, Akira*; Takeda, Yukiharu; Okane, Tetsuo; Saito, Yuji; Fujimori, Atsushi; Yamagami, Hiroshi; Haga, Yoshinori; et al.
Physical Review B, 91(17), p.174503_1 - 174503_9, 2015/05
Times Cited Count：25 Percentile：70.17(Materials Science, Multidisciplinary)The electronic structures of the ferromagnetic superconductors UGe and UCoGe in the paramagnetic phase were studied by angle-resolved photoelectron spectroscopy using soft X-rays (
= 400-500 eV). The quasi-particle bands with large contributions from U 5 states were observed in the vicinity of EF, suggesting that the U 5 electrons of these compounds have an itinerant character. Their overall band structures were explained by the band-structure calculations treating all the U 5 electrons as being itinerant. Meanwhile, the states in the vicinity of EF show considerable deviations from the results of band-structure calculations, suggesting that the shapes of Fermi surface of these compounds are qualitatively different from the calculations, possibly caused by electron correlation effect in the complicated band structures of the low-symmetry crystals. Strong hybridization between U 5 and 
states in UCoGe were found by the 
2p-3d resonant photoemission experiment, suggesting that states have finite contributions to the magnetic, transport, and superconducting properties.
AlFujimori, Shinichi; Kawasaki, Ikuto*; Yasui, Akira*; Takeda, Yukiharu; Okane, Tetsuo; Saito, Yuji; Fujimori, Atsushi; Yamagami, Hiroshi; Haga, Yoshinori; Yamamoto, Etsuji; et al.
JPS Conference Proceedings (Internet), 3, p.011072_1 - 011072_5, 2014/06
In this presentation, we review some of our recent photoemission studies on uranium superconductors by means of soft X-ray synchrotron radiation ARPES (SX-ARPES). Results of SX-ARPES study on URhGe and UPdAl will be presented. URhGe is a ferromagnetic superconductor with 
= 9.5 K and 
= 0.26 K while UPdAl is an antiferromagnetic superconductor with 
= 14 K and = 1.8 K. We have revealed the three-dimensional electronic structures of those compounds by SX-ARPES, and they are compared with those calculated by LDA.
Fujimori, Shinichi; Kawasaki, Ikuto*; Yasui, Akira*; Takeda, Yukiharu; Okane, Tetsuo; Saito, Yuji; Fujimori, Atsushi*; Yamagami, Hiroshi; Haga, Yoshinori; Yamamoto, Etsuji; et al.
Physical Review B, 89(10), p.104518_1 - 104518_7, 2014/03
Times Cited Count：21 Percentile：64.83(Materials Science, Multidisciplinary)The electronic structure of the ferromagnetic superconductor URhGe in the paramagnetic phase has been studied by angle-resolved photoelectron spectroscopy using soft X rays (
= 595-700 eV). Dispersive bands with large contributions from U 5 states were observed in the ARPES spectra, and form Fermi surfaces. The band structure in the paramagnetic phase is partly explained by the band-structure calculation treating all U 5 electrons as being itinerant, suggesting that an itinerant description of U 5 states is a good starting point for this compound. On the other hand, there are qualitative disagreements especially in the band structure near the Fermi level (
0.5 eV). The experimentally observed bands are less dispersive than the calculation, and the shape of the Fermi surface is different from the calculation. The changes in spectral functions due to the ferromagnetic transition were observed in bands near the Fermi level, suggesting that the ferromagnetism in this compound has an itinerant origin.
Si using soft X-ray angle-resolved photoemission spectroscopyYasui, Akira*; Saito, Yuji; Fujimori, Shinichi; Kawasaki, Ikuto*; Okane, Tetsuo; Takeda, Yukiharu; Lapertot, G.*; Knebel, G.*; Matsuda, Tatsuma*; Haga, Yoshinori; et al.
Physical Review B, 87(7), p.075131_1 - 075131_6, 2013/02
Times Cited Count：6 Percentile：29.2(Materials Science, Multidisciplinary)We have performed soft X-ray angle-resolved photoemission spectroscopy (ARPES) measurements on YbRhSi and clarified its three-dimensional bulk valence-band structures. The ARPES spectra have not only Yb multiplet peaks but also a finite contribution of Yb
peaks at 15 K, corresponding to the valence fluctuating behavior in this compound. This means that Yb 4f electrons in this compound have itinerant character below the 
. We have found that dispersions of the valence bands except the vicinity of the Yb 4f bands agree better with those of the band-structure calculation of LuRhSi than those of YbRhSi within a local-density approximation. In addition, the Yb 3d-4f resonant photoemission spectra of YbRhSi strongly suggest the existence of Yb 5d electrons in the valence band. We conclude that the charge transfer from the Yb 4f state to the Yb 5d state has an important role in the formation of the valence band of YbRhSi.
Fujimori, Shinichi; Okochi, Takuo*; Kawasaki, Ikuto; Yasui, Akira; Takeda, Yukiharu; Okane, Tetsuo; Saito, Yuji; Fujimori, Atsushi; Yamagami, Hiroshi; Haga, Yoshinori; et al.
Journal of the Physical Society of Japan, 81(1), p.014703_1 - 014703_9, 2012/01
Times Cited Count：37 Percentile：81.99(Physics, Multidisciplinary)High-energy-resolution core-level and valence-band photoelectron spectroscopic studies were performed for the heavy Fermion uranium compounds UGe, UCoGe, URhGe, URuSi, UNiAl, UPdAl, and UPt as well as typical localized and itinerant uranium compounds to understand the relationship between the uranium valence state and their core-level spectral line shapes. The core-level spectra of UGe, UCoGe, URhGe, URuSi, and UNiAl are rather similar to those of itinerant compounds, suggesting that U 5 electrons in these compounds are well hybridized with ligand states. On the other hand, the core-level spectra of UPdAl and UPt show considerably different spectral line shapes from those of the itinerant compounds, suggesting that U 5 electrons in UPdAl and UPt are less hybridized with ligand states, leading to the correlated nature of U 5 electrons in these compounds.
nature in antiferromagnet U(Ru
Rh
)Si; Soft X-ray angle-resolved photoemission spectroscopyKawasaki, Ikuto; Fujimori, Shinichi; Okane, Tetsuo; Yasui, Akira; Saito, Yuji; Yamagami, Hiroshi*; Haga, Yoshinori; Yamamoto, Etsuji; Onuki, Yoshichika*
Journal of the Physical Society of Japan, 80(12), p.124710_1 - 124710_5, 2011/12
Times Cited Count：6 Percentile：43.21(Physics, Multidisciplinary)We have carried out soft X-ray angle-resolved photoemission spectroscopy experiments on U(RuRh)Si, which shows antiferromagnetic (AFM) ordering at low temperatures. We have revealed that U 5 electrons contribute to the formation of the energy band as well as Fermi surface. This suggests that the AFM ordering is caused by a spin density wave of itinerant U 5 electrons. The observed band dispersion and Fermi surface are nearly identical to those of URuSi. Therefore, the AFM ordering vector 
= (1,0,0) can be a possible ordering vector of the hidden order phase in URuSi.
Ge studied by soft X-ray angle-resolved photoemission spectroscopyYasui, Akira; Fujimori, Shinichi; Kawasaki, Ikuto; Okane, Tetsuo; Takeda, Yukiharu; Saito, Yuji; Yamagami, Hiroshi; Sekiyama, Akira*; Settai, Rikio*; Matsuda, Tatsuma; et al.
Physical Review B, 84(19), p.195121_1 - 195121_6, 2011/11
Times Cited Count：8 Percentile：36.01(Materials Science, Multidisciplinary)We have measured three-dimensional band structure and Fermi surfaces (FSs) of YbCuGe, which has recently become recognized as a nearly divalent Yb-based compound, by using soft X-ray angle-resolved photoemission spectroscopy. We clarified that the bands with finite Yb 4 contribution cross the Fermi level and are slightly involved in the formation of the FSs, in line with the valence-fluctuating state of YbCuGe. The obtained valence-band dispersions and the FSs are well explained by a relativistic band-structure calculation based on a local-density-approximation (LDA). These results suggest that the LDA calculation is a good starting point for understanding of the electronic state of YbCuGe as well as nearly divalent Yb-based compounds.
