Control of spin currents by magnon interference in a canted antiferromagnet

Sheng, L.*; Yamamoto, Kei; 18 of others*

Nature Physics, 8 Pages, 2025/04

https://doi.org/10.1038/s41567-025-02819-7

Room-temperature flexible manipulation of the quantum-metric structure in a topological chiral antiferromagnet

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

https://doi.org/10.1038/s41567-024-02476-2

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 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.

Discrete degeneracies distinguished by the anomalous Hall effect in a metallic kagome ice compound

Zhao, K.*; Tokiwa, Yoshifumi; Chen, H.*; Gegenwart, P.*

Nature Physics, 20(3), p.442 - 449, 2024/03

https://doi.org/10.1038/s41567-023-02307-w

In magnetic crystals, despite the explicit breaking of time-reversal symmetry, two equilibrium states related by time reversal are always energetically degenerate. In ferromagnets, this time-reversal degeneracy is reflected in the hysteresis of the magnetic field dependence of the magnetization and, if metallic, in that of the anomalous Hall effect (AHE). Under time-reversal, both these quantities change signs but not their magnitude. Here we show that a time-reversal-like degeneracy appears in the metallic kagome spin ice HoAgGe when magnetic fields are applied parallel to the kagome plane. We find vanishing hysteresis in the field dependence of the magnetization at low temperature, but finite hysteresis in the field-dependent AHE. This suggests the emergence of states with nearly the same energy and net magnetization but different sizes of the AHE and of the longitudinal magnetoresistance. By analysing the experimental data and a minimal tight-binding model, we identify a time-reversal-like operation connecting these near-degenerate states, which is related to the non-trivial distortion of the kagome lattice in HoAgGe. Our work demonstrates the diagnostic power of transport phenomena for identifying hidden symmetries in frustrated spin systems.

Spontaneous topological Hall effect induced by non-coplanar antiferromagnetic order in intercalated van der Waals materials

Takagi, Hirotaka*; Takagi, Rina*; Minami, Susumu*; Nomoto, Takuya*; Oishi, Kazuki*; Suzuki, Michito*; Yanagi, Yuki*; Hirayama, Motoaki*; Khanh, N.*; Karube, Kosuke*; et al.

Nature Physics, 19(7), p.961 - 968, 2023/07

https://doi.org/10.1038/s41567-023-02017-3

Creation of quark-gluon plasma droplets with three distinct geometries

Aidala, C.*; Hasegawa, Shoichi; Imai, Kenichi; Sako, Hiroyuki; Sato, Susumu; Tanida, Kiyoshi; PHENIX Collaboration*; 312 of others*

Nature Physics, 15(3), p.214 - 220, 2019/03

https://doi.org/10.1038/s41567-018-0360-0

Spin pumping from nuclear spin waves

Shiomi, Yuki*; Lustikova, J.*; Watanabe, Shingo*; Hirobe, Daichi*; Takahashi, Saburo*; Saito, Eiji

Nature Physics, 15(1), p.22 - 26, 2018/10

https://doi.org/10.1038/s41567-018-0310-x

One-dimensional spinon spin currents

Hirobe, Daichi*; Sato, Masahiro*; Kawamata, Takayuki*; Shiomi, Yuki*; Uchida, Kenichi*; Iguchi, Ryo*; Koike, Yoji*; Maekawa, Sadamichi; Saito, Eiji

Nature Physics, 13(1), p.30 - 34, 2017/01

https://doi.org/10.1038/nphys3895

Colossal thermomagnetic response in the exotic superconductor URuSi

Yamashita, Takuya*; Shimoyama, Yusuke*; Haga, Yoshinori; Matsuda, Tatsuma*; Yamamoto, Etsuji; Onuki, Yoshichika; Sumiyoshi, Hiroaki*; Fujimoto, Satoshi*; Levchenko, A.*; Shibauchi, Takasada*; et al.

Nature Physics, 11(1), p.17 - 20, 2015/01

https://doi.org/10.1038/nphys3170

Polaron spin current transport in organic semiconductors

Watanabe, Shun*; Ando, Kazuya*; Kang, K.*; Mooser, S.*; Vaynzof, Y.*; Kurebayashi, Hidekazu*; Saito, Eiji; Sirringhaus, H.*

Nature Physics, 10(4), p.308 - 313, 2014/04

https://doi.org/10.1038/nphys2901

Emergent rank-5 nematic order in URuSi

Ikeda, Hiroaki*; Suzuki, Michito; Arita, Ryotaro*; Takimoto, Tetsuya*; Shibauchi, Takasada*; Matsuda, Yuji*

Nature Physics, 8(7), p.528 - 533, 2012/07

https://doi.org/10.1038/nphys2330

The origin of the hidden-order phase transition of URuSi has been a long-standing mystery in condensed matter physics. We examine the complete set of multipole correlations allowed in URuSi based on a first-principles theoretical approach. The results uncover that the hidden-order parameter is a rank-5 multipole (dotriacontapole) order with nematic symmetry. This naturally provides comprehensive explanations of all key features in the hidden-order phase including anisotropic magnetic excitations, nearly degenerate antiferromagnetic-ordered state, and spontaneous rotational symmetry breaking.