S
S. Niitaka
Researcher at University of Tokyo
Publications - 11
Citations - 647
S. Niitaka is an academic researcher from University of Tokyo. The author has contributed to research in topics: Superconductivity & Infrared spectroscopy. The author has an hindex of 7, co-authored 11 publications receiving 588 citations.
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Journal ArticleDOI
Unconventional s-wave superconductivity in Fe(Se,Te).
TL;DR: In this article, the authors used scanning tunneling microscopy on Fe(Se,Te) single crystals to image the quasi-particle scattering interference patterns in the superconducting state.
Journal ArticleDOI
Anomalous metallic state in the vicinity of metal to valence-bond solid insulator transition in LiVS2.
Naoyuki Katayama,Masaya Uchida,Daisuke Hashizume,S. Niitaka,Jobu Matsuno,Daiju Matsumura,Yasuo Nishihata,Jun'ichiro Mizuki,Nao Takeshita,A. Gauzzi,A. Gauzzi,Minoru Nohara,H. Takagi,H. Takagi +13 more
TL;DR: It is argued that the high temperature metallic phase of LiVS2 has a pseudogap, likely originating from the VBS fluctuation, and LiVSe2 was found to be a paramagnetic metal down to 2 K.
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Evidence for a cos(4φ) modulation of the superconducting energy gap of optimally doped FeTe(0.6)Se(0.4) single crystals using laser angle-resolved photoemission spectroscopy.
Kozo Okazaki,Y. Ito,Yasutomo Ota,Yoshinori Kotani,Takahiro Shimojima,Takayuki Kiss,Shuntaro Watanabe,C. T. Chen,S. Niitaka,Tetsuo Hanaguri,H. Takagi,A. Chainani,Shik Shin +12 more
TL;DR: The observed SC-gap anisotropy strongly indicates that the pairing interaction is not a conventional phonon-mediated isotropic one and suggests the importance of second-nearest-neighbor electronic interactions between the iron sites in the framework of s(±)-wave superconductivity.
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Phonon, two-magnon, and electronic Raman scattering of Fe 1 + y Te 1 − x Se x
TL;DR: In this paper, the authors measured Raman-scattering spectra of single-crystalline FeTe and its parent compound Fe{}_{1.074}$Te at various temperatures.
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Do all nuclei recoil on photoemission in compounds
Shigemasa Suga,Akira Sekiyama,Hideki Fujiwara,Y. Nakatsu,T. Miyamachi,Shin Imada,Shin Imada,P Baltzer,S. Niitaka,Hidenori Takagi,Kazuyoshi Yoshimura,Makina Yabashi,Kenji Tamasaku,Atsushi Higashiya,T. Ishikawa +14 more
TL;DR: Hard and soft x-ray photoelectron spectroscopy was performed for core and valence electrons in solid compounds containing V and O atoms as mentioned in this paper, and the single-nucleus recoil effects on photo electron emission were observed in the form of recoil shifts for all core levels and the valence band in a heavy Fermion material LiV2O4, whereas such shifts were negligible in VO2 even in the high-temperature metal phase.