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Yoon, J.-Y.*; Takeuchi, Yutaro*; Takechi, Ryota*; Han, J.*; Uchiyama, Tomohiro*; Yamane, Yuta*; Kanai, Shun*; Ieda, Junichi; Ohno, Hideo*; Fukami, Shunsuke*
Nature Communications (Internet), 16, p.1171_1 - 1171_8, 2025/02
Times Cited Count：0 Percentile：0.00(Multidisciplinary Sciences)Han, J.*; Uchimura, Tomohiro*; Araki, Yasufumi; Yoon, J.-Y.*; Takeuchi, Yutaro*; Yamane, Yuta*; Kanai, Shun*; Ieda, Junichi; Ohno, Hideo*; Fukami, Shunsuke*
Nature Physics, 20(7), p.1110 - 1117, 2024/07
Times Cited Count：8 Percentile：94.14(Physics, Multidisciplinary)Quantum metric and Berry curvature are two fundamental and distinct factors to describe the geometry of quantum eigenstates. While Berry curvature is known for playing crucial roles in several condensed-matter states, quantum metric, which was predicted to induce new classes of topological phenomena, has rarely been touched, particularly in an ambient circumstance. Using a topological chiral antiferromagnet Mn
Sn adjacent to Pt, at room temperature, we successfully manipulate the quantum-metric structure of electronic states through its interplay with the nanoscale spin texture at the MnSn/Pt interface. This is manifested by a time-reversal-odd second-order Hall effect that is robust against extrinsic electron scattering, in contrast to any transport effects from the Berry curvature. We also verify the flexibility of controlling the quantum-metric structure, as the interacting spin texture can be tuned by moderate magnetic fields or by interface engineering via spin-orbit interactions. Our work paves a way for harnessing the quantum-metric structure to unveil emerging topological physics in practical environments and to build applicable nonlinear devices.
Sn nanodotSato, Yuma*; Takeuchi, Yutaro*; Yamane, Yuta*; Yoon, J.-Y.*; Kanai, Shun*; Ieda, Junichi; Ohno, Hideo*; Fukami, Shunsuke*
Applied Physics Letters, 122(12), p.122404_1 - 122404_5, 2023/03
Times Cited Count：4 Percentile：54.88(Physics, Applied)Funatsu, Takuya*; Kanai, Shun*; Ieda, Junichi; Fukami, Shunsuke*; Ohno, Hideo*
Nature Communications (Internet), 13, p.4079_1 - 4079_8, 2022/07
Times Cited Count：8 Percentile：57.43(Multidisciplinary Sciences)Modulation of the energy landscape by external perturbations governs various thermally-activated phenomena, described by the Arrhenius law. Thermal fluctuation of nanoscale magnetic tunnel junctions with spin-transfer torque (STT) shows promise for unconventional computing, whereas its rigorous representation, based on the Neel-Arrhenius law, has been controversial. In particular, the exponents for thermally-activated switching rate therein, have been inaccessible with conventional thermally-stable nanomagnets with decade-long retention time. Here we approach the Neel-Arrhenius law with STT utilising superparamagnetic tunnel junctions that have high sensitivity to external perturbations and determine the exponents through several independent measurements including homodyne-detected ferromagnetic resonance, nanosecond STT switching, and random telegraph noise. Furthermore, we show that the results are comprehensively described by a concept of local bifurcation observed in various physical systems. The findings demonstrate the capability of superparamagnetic tunnel junction as a useful tester for statistical physics as well as sophisticated engineering of probabilistic computing hardware with a rigorous mathematical foundation.
Sn thin films by magneto-optical Kerr effectUchimura, Tomohiro*; Yoon, J.-Y.*; Sato, Yuma*; Takeuchi, Yutaro*; Kanai, Shun*; Takechi, Ryota*; Kishi, Keisuke*; Yamane, Yuta*; DuttaGupta, S.*; Ieda, Junichi; et al.
Applied Physics Letters, 120(17), p.172405_1 - 172405_5, 2022/04
Times Cited Count：22 Percentile：87.95(Physics, Applied)Takeuchi, Yutaro*; Yamane, Yuta*; Yoon, J.-Y.*; Ito, Ryuichi*; Jinnai, Butsurin*; Kanai, Shun*; Ieda, Junichi; Fukami, Shunsuke*; Ohno, Hideo*
Nature Materials, 20(10), p.1364 - 1370, 2021/10
Times Cited Count：121 Percentile：98.78(Chemistry, Physical)
Sn
thin filmsYoon, J.-Y.*; Takeuchi, Yutaro*; DuttaGupta, S.*; Yamane, Yuta*; Kanai, Shun*; Ieda, Junichi; Ohno, Hideo*; Fukami, Shunsuke*
AIP Advances (Internet), 11(6), p.065318_1 - 065318_6, 2021/06
Times Cited Count：18 Percentile：76.47(Nanoscience & Nanotechnology)Okada, Atsushi*; He, S.*; Gu, B.; Kanai, Shun*; Soumyanarayanan, A.*; Lim, S. T.*; Tran, M.*; Mori, Michiyasu; Maekawa, Sadamichi; Matsukura, Fumihiro*; et al.
Proceedings of the National Academy of Sciences of the United States of America, 144(15), p.3815 - 3820, 2017/04
ions with Ba atomsIemura, K.*; Otani, Shunsuke*; Suzuki, H.*; Takeda, Junichi*; Machida, Shuichi*; Tanabe, K.*; Takayanagi, Toshinobu*; Wakiya, K.*; Sekiguchi, M.*; Kanai, Yasuyuki*; et al.
Physical Review A, 64(6), p.062709_1 - 062709_14, 2001/12
Times Cited Count：6 Percentile：35.34(Optics)We measured ejected electron spectra caused by autoionization of doubly excited states in He atoms; the excited He was made by double electron capture of low-energy He ions colliding with Ba atoms. Measurements were performed by means of zero degree electron spectroscopy at projectile energies from 40 to 20 keV. Electron spectra due to autoionization from the states He(2lnl) to He+(1s) for n
2, and those from He(3lnl) to He
(2s or 2p) for n3, were observed. Line peaks in the spectra were identified by comparing observed electron spectra with those of several theoretical calculations. It was found that doubly excited states of relatively high angular momenta such as the D and F terms were conspicuously created in a quite different manner from the cases of the production of doubly excited states by the use of photon, electron, or ion impacts on neutral He atoms. Rydberg states with large n values were observed with high population in both the He(2lnl) and He(3lnl) series.
produced by low energy Ne
+He, Ne and Ar collisionsKitazawa, Shinichi; Ida, H.*; Matsui, Y.*; Takayanagi, Toshinobu*; Wakiya, K.*; Iemura, K.*; Otani, Shunsuke*; Suzuki, H.*; Kanai, Yasuyuki*; Safronova, U. I.*
Journal of Physics B; Atomic, Molecular and Optical Physics, 34(16), p.3205 - 3220, 2001/08
Times Cited Count：5 Percentile：31.13(Optics)no abstracts in English
ions with aklaline-earth atomsIemura, K.*; Suzuki, H.*; Otani, Shunsuke*; Takeda, Junichi*; Takayanagi, Toshinobu*; Wakiya, K.*; Sekiguchi, M.*; Kanai, Yasuyuki*; Kitazawa, Shinichi; Tong, X. M.*; et al.
Atomic Collision Research in Japan, No.25, p.42 - 43, 1999/11
no abstracts in English
Kageyama, H.*; Kawatsura, Kiyoshi*; Takahashi, R.*; Arai, Shigeyoshi*; Kambara, Tadashi*; Oura, Masaki*; Papp, T.*; Kanai, Yasuyuki*; Awaya, Yoko*; Takeshita, Hidefumi; et al.
Nuclear Instruments and Methods in Physics Research B, 107(1-4), p.47 - 50, 1996/00
Times Cited Count：2 Percentile：31.76(Instruments & Instrumentation)no abstracts in English
Han, J.*; Uchimura, Tomohiro*; Araki, Yasufumi; Yoon, J.-Y.*; Takeuchi, Yutaro*; Yamane, Yuta*; Kanai, Shun*; Ieda, Junichi; Ohno, Hideo*; Fukami, Shunsuke*
no journal, ,
Han, J.*; Uchimura, Tomohiro*; Araki, Yasufumi; Yoon, J.-Y.*; Takeuchi, Yutaro*; Yamane, Yuta*; Kanai, Shun*; Ieda, Junichi; Ohno, Hideo*; Fukami, Shunsuke*
no journal, ,
no abstracts in English
