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Nakata, Koki; Suzuki, Kei
npj Spintronics (Internet), 2, p.11_1 - 11_6, 2024/06
To explore and utilize even dissipation is a crucial issue of spintronics. Here, we shed light on this problem by using a quantum effect, called the magnonic Casimir effect. We show that the dissipation caused by the Gilbert damping decreases the magnon energy gap, and it enhances the magnonic Casimir energy. Then, we find that this magnonic non-Hermitian Casimir effect exhibits an oscillating behavior as a function of the film thickness, and the oscillation is characterized by the exceptional point. Our result suggests that dissipation can serve as a key ingredient of Casimir engineering. Microfabrication technology can control the thickness of thin films and realize the manipulation of the magnonic non-Hermitian Casimir effect. Thus, we pave the way for magnonic Casimir engineering.
Han, J.*; Uchimura, Tomohiro*; Araki, Yasufumi; Yoon, J.-Y.*; Takeuchi, Yutaro*; Yamane, Yuta*; Kanai, Shun*; Ieda, Junichi; Ohno, Hideo*; Fukami, Shunsuke*
Nature Physics, 21 Pages, 2024/04
Times Cited Count:0 Percentile:0.01Quantum 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 MnSn 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.
Lee, S.*; Nakata, Koki; Tchernyshyov, O.*; Kim, S. K.*
Physical Review B, 107(18), p.184432_1 - 184432_12, 2023/05
Times Cited Count:5 Percentile:89.29(Materials Science, Multidisciplinary)We theoretically investigate the interaction between magnons and a Skyrmion-textured domain wall in a two-dimensional antiferromagnet and elucidate the resultant properties of magnon transport. Using supersymmetric quantum mechanics, we solve the scattering problem of magnons on top of the domain wall and obtain the exact solutions of propagating and bound magnon modes. Then, we find their properties of reflection and refraction in the Skyrmion-textured domain wall, where magnons experience an emergent magnetic field due to its non-trivial spin texture-induced effective gauge field. Finally, we show that the thermal transport decreases as the domain wall's chirality increases. Our results suggest that the thermal transport of an antiferromagnet is tunable by modulating the Skyrmion charge density of the domain wall.
Sato, 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:2 Percentile:66.71(Physics, Applied)Uchimura, 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:11 Percentile:85.25(Physics, Applied)Schreiber, F.*; Meer, H.*; Schmitt, C.*; Ramos, R.*; Saito, Eiji; Baldrati, L.*; Klui, M.*
Physical Review Applied (Internet), 16(6), p.064023_1 - 064023_9, 2021/12
Times Cited Count:3 Percentile:25.71(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:84 Percentile:98.69(Chemistry, Physical)Shamoto, Shinichi; Yamauchi, Hiroki; Ikeuchi, Kazuhiko*; Lee, M. K.*; Chang, L.-J.*; Garlea, V. O.*; Hwang, I. Y.*; Lee, K. H.*; Chung, J.-H.*
Journal of the Physical Society of Japan, 90(9), p.093703_1 - 093703_4, 2021/09
Times Cited Count:0 Percentile:0.00(Physics, Multidisciplinary)no abstracts in English
Yoon, 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:14 Percentile:77.78(Nanoscience & Nanotechnology)Hwang, I. Y.*; Lee, K. H.*; Chung, J.-H.*; Ikeuchi, Kazuhiko*; Garlea, V. O.*; Yamauchi, Hiroki; Akatsu, Mitsuhiro*; Shamoto, Shinichi
Journal of the Physical Society of Japan, 90(6), p.064708_1 - 064708_6, 2021/06
Times Cited Count:2 Percentile:28.62(Physics, Multidisciplinary)no abstracts in English
Sakai, Hironori; Matsumoto, Yuji*; Haga, Yoshinori; Tokunaga, Yo; Kambe, Shinsaku
Physical Review B, 103(8), p.085114_1 - 085114_8, 2021/02
Times Cited Count:0 Percentile:0.00(Materials Science, Multidisciplinary)The microscopic origin of a magnetic phase diagram under pressure in a heavy fermion antiferromagnet CeRhSi was investigated using the Si nuclear magnetic resonance (NMR) technique. We investigated the temperature and pressure dependencies of -independent local fluctuations caused by the single-site Kondo effect. A universal scaling behavior observed on the energy scale of the local fluctuations in an entire pressure region demonstrates that a characteristic energy scale of Kondo interactions monotonically increases by applying pressure without a critical anomaly around the quantum critical pressure of antiferromagnetism. Our NMR result agrees with the Doniach picture of the heavy-fermion phase diagram, where the progressive delocalization of the -electrons occurs across , accompanied by the development of antiferromagnetic correlations among the -electrons.
Meer, H.*; Schreiber, F.*; Schmitt, C.*; Ramos, R.*; Saito, Eiji; Gomonay, O.*; Sinova, J.*; Baldrati, L.*; Klui, M.*
Nano Letters, 21(1), p.114 - 119, 2021/01
Times Cited Count:54 Percentile:97.02(Chemistry, Multidisciplinary)Baldrati, L.*; Schmitt, C.*; Gomonay, O.*; Lebrun, R.*; Ramos, R.*; Saito, Eiji; Sinova, J.*; Klui, M.*
Physical Review Letters, 125(7), p.077201_1 - 077201_6, 2020/08
Times Cited Count:36 Percentile:91.19(Physics, Multidisciplinary)Fujihara, Masayoshi*; Morita, Katsuhiro*; Mole, R.*; Mitsuda, Setsuo*; Toyama, Takami*; Yano, Shinichiro*; Yu, D.*; Sota, Shigetoshi*; Kuwai, Tomohiko*; Koda, Akihiro*; et al.
Nature Communications (Internet), 11, p.3429_1 - 3429_7, 2020/07
Times Cited Count:39 Percentile:92.16(Multidisciplinary Sciences)Baldrati, L.*; Gomonay, O.*; Ross, A.*; Filianina, M.*; Lebrun, R.*; Ramos, R.*; Leveille, C.*; Fuhrmann, F.*; Forrest, T. R.*; Maccherozzi, F.*; et al.
Physical Review Letters, 123(17), p.177201_1 - 177201_6, 2019/10
Times Cited Count:118 Percentile:98.30(Physics, Multidisciplinary)Yamane, Yuta*; Ieda, Junichi
Magune, 13(5), p.235 - 241, 2018/10
Ieda, Junichi; Barnes, S. E.*; Maekawa, Sadamichi
Journal of the Physical Society of Japan, 87(5), p.053703_1 - 053703_4, 2018/05
Times Cited Count:5 Percentile:41.01(Physics, Multidisciplinary)Ito, Saya*; Kurita, Nubuyuki*; Tanaka, Hidekazu*; Kawamura, Seiko; Nakajima, Kenji; Ito, Shinichi*; Kuwahara, Keitaro*; Kakurai, Kazuhisa*
Nature Communications (Internet), 8, p.235_1 - 235_6, 2017/08
Times Cited Count:76 Percentile:94.04(Multidisciplinary Sciences)Nakano, Hiroki*; Sakai, Toru
Journal of Physics; Conference Series, 868, p.012006_1 - 012006_10, 2017/07
Times Cited Count:3 Percentile:78.28(Physics, Applied)The spin gap issue of the kagome lattice antiferromagnet is investigated by the finite size scaling analysis applied for the energy spectrum of the rhombic clusters calculated by the numerical exact diagonalization. The conclusion is that the kagome lattice antiferromagnet is gapless, as well as the triangular lattice one.
Yamane, Yuta*; Ieda, Junichi; Sinova, J.*
Physical Review B, 94(5), p.054409_1 - 054409_8, 2016/08
Times Cited Count:28 Percentile:75.32(Materials Science, Multidisciplinary)We formulate a theory of spin-transfer torques in antiferromagnets, which covers the small to large limits of the exchange coupling energy relative to the kinetic energy of the inter-sublattice electron dynamics. Our theory suggests a natural definition of the efficiency of spin-transfer torques in antiferromagnets in terms of well-defined material parameters, revealing that the charge current couples predominantly to the antiferromagnetic order parameter and the sublattice-canting moment in, respectively, the limits of large and small exchange coupling. The effects can be quantified by analyzing the antiferromagnetic spin-wave dispersions in the presence of charge current: in the limit of large exchange coupling the spin-wave Doppler shift always occurs, whereas, in the opposite limit, the only spin-wave modes to react to the charge current are ones that carry a pronounced sublattice-canting moment. The findings offer a framework for understanding and designing spin-transfer torques in antiferromagnets belonging to different classes of sublattice structures such as, e.g., bipartite and layered antiferromagnets.