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Sb
with an ordered honeycomb network今津 毅士; 古谷 直也*; 足立 匡*; 工藤 一貴*; 今井 剛樹*; 御領 潤*
Journal of the Physical Society of Japan, 95(4), p.044704_1 - 044704_7, 2026/04
空間反転対称性を破る結晶構造をもつ蜂の巣格子超伝導体BaPtAsSbは超伝導転移温度のx依存性が非単調な振る舞いを示す。更にミューオンスピン緩和実験によりSbエンド(
=1)において自発磁場が観測され、時間反転対称性を破る超伝導状態が実現している可能性がある。BaPtAs(=0), BaPtSb(=1)の第一原理計算を行い、バンド構造を再現する有効強束縛模型を用いてギャップ方程式と凝縮エネルギーの解析を行い、安定となる超伝導対称性を議論した。その結果、BaPtAs(=0)では時間反転対称性のある従来型のs波超伝導とf波超伝導が安定化し、BaPtSb(=1)では時間反転対称性を破るカイラルd波状態が広く安定化することがわかった。この結果はミューオンスピン緩和実験とも整合する。また本論文で得られた知見は六方晶におけるカイラル超伝導相の探索に重要な指針を与える。
Zn
Mo
O
Bao, S.*; Liao, J.*; Huang, Z.*; Shangguan, Y.*; Ma, Z.*; Zhang, B.*; Cheng, S.*; Xu, H.*; Song, Z.*; Dong, S.*; et al.
Physical Review Letters, 136(9), p.096502_1 - 096502_8, 2026/03
Lattice vibrations can carry angular momentum and magnetic moments under broken inversion or time-reversal symmetry, forming so-called chiral phonons. While such excitations have been explored in nonmagnetic systems via optical probes, their direct detection in magnetic materials and coupling to spin excitations remain largely unexplored. Here, using neutron spectroscopy, sensitive to both nuclear and magnetic scattering, we reveal the magnetic signature of chiral phonons in ferrimagnetic FeZnMoO with Curie temperature 
K. Below 
, we observe enhanced magnetic scattering of phonons at small momenta, arising from strong magnon-phonon coupling. In addition, out-of-plane intensity modulation, phonon mode splitting, and field-induced Zeeman shifts are observed, all closely associated with the ferrimagnetic order. These features vanish above , where phonon spectra are dominated by nuclear scattering. These observations demonstrate the existence of chiral phonons carrying substantial magnetic moments that directly contribute to magnetic scattering, and establish neutron spectroscopy as a powerful, momentum-resolved probe of their magnetic character.
SbO
Piyakulworawat, C.*; 森田 克洋*; 福元 好志*; Hsieh, W.-Y.*; Chen, W.-T.*; 中島 健次; 河村 聖子; Zhao, Y.*; Wannapaiboon, S.*; Piyawongwatthana, P.; et al.
Physical Review Research (Internet), 8(1), p.013247_1 - 013247_16, 2026/03
歪んだハニカム化合物CuSbOの中性子非弾性散乱および磁化データを、一次のダイマー展開計算と量子モンテカルロシミュレーションを用いて解析した。これまでに提案されたハニカム格子モデルとは対照的に、この系は相互作用するダイマースピン鎖を有し、鎖に沿って強磁性-反強磁性結合が交互に現れることが示された。さらに、他のCu
ベースの歪んだハニカム磁性体で観測される典型的な結合とは異なり、スピン鎖は、予想される層間の鎖間結合ではなく、主にハニカム層間に生じる反強磁性結合を介して結合する。つまり、CuSbOの磁気結合スキームが異なることが明らかになった。さらに、X線分光法と透過型電子顕微鏡を利用して、化合物の結晶構造と積層欠陥モデルも従来のモデルをより精密化した。
藤原 理賀; 萩原 雅人; 石角 元志*; Sari, D. P.*; 渡邊 功雄*; 髭本 亘; 田端 千紘; 金子 耕士
Physical Review B, 113(6), p.064409_1 - 064409_8, 2026/02
被引用回数：0We report a field-induced quantum first-order transition in the antiferromagnet KCoPO
H
O. Using highly oriented microcrystals with 
, polarized neutron diffraction directly reveals coexistence of an incommensurate cycloid and a commensurate collinear state, together with a discontinuous jump of the ordering wave vector from incommensurate to commensurate. Magnetization and specific heat show a step and a collapse of the 
anomaly near 
~T with no measurable hysteresis, while LF-
SR detects two-component relaxation and slow fluctuations around 
. The 
-
phase diagram exhibits a narrow coexistence region. Symmetry of space group 
constrains the DM vector to the 
plane and, together with XY anisotropy, nearly degenerates the incommensurate and commensurate states, enabling a first-order switch in field. KCoPOHO thus serves as a platform for quantum first-order transitions in frustrated magnets.
-decay strength of 
VDahl, J. K.*; Larsen, A. C.*; 清水 則孝*; 宇都野 穣
Physical Review C, 113(2), p.024328_1 - 024328_16, 2026/02
Vに対する核準位密度とガンマ線強度関数を、
-
-
殻をバレンス殻にとった大規模殻模型計算によって調べた。オスロ法による実験データを全体的によく説明し、特に、低エネルギーの
遷移の強度が増大するという特徴を再現することに成功した。そのメカニズムを解明するために、遷移の行列要素を軌道角運動量部分とスピン角運動量部分に分け、その干渉項の符号の分布を調べた。その結果、低エネルギーガンマ崩壊に対しては、正の干渉が主であるという新しい知見が得られた。
石飛 尊之; 服部 一匡*
Physical Review Letters, 136(5), p.056402_1 - 056402_6, 2026/02
被引用回数：0We propose purely electronic chirality (pEC), a chiral electronic state that emerges without any structural chirality. As a promising feature, we show that its handedness can be controlled by magnetic fields and illustrate this with a model of 120-degree antiferro quadrupole order on a distorted kagome lattice, relevant to the nonmagnetic ordered phase of URhSn. We also demonstrate that chiral phonons can appear in achiral crystals through coupling to pEC. This provides a new electronic origin of chirality and a basis for studying its connection to structural chirality.
Chen, J.*; 山本 慧; 他13名*
Physical Review Letters, 136(5), p.056702_1 - 056702_8, 2026/02
被引用回数：0The recently developed van der Waals magnets provide a promising platform for spintronics and magnonics. Here, we report the observation of surface magnon propagation in the van der Waals antiferromagnet CrSBr. We find a nearly unidirectional propagation of antiferromagnetic magnon modes, which emerge near the anticrossing of the optical and acoustic magnon bands, in agreement with our theory of magnetostatic waves in antiferromagnets. The propagation direction can be reversed by switching the magnetic field. The observed antiferromagnetic magnons operate in the gigahertz regime due to the weak interlayer exchange coupling. Our results open the pathway for nonreciprocal magnonic applications based on van der Waals antiferromagnets at easily-accessible microwave frequencies.
Wang, M.*; 坂牛 健*; 辻 卓也; 松村 大樹; 他9名*
Journal of Physical Chemistry C, 130(2), p.931 - 941, 2026/01
被引用回数：0 パーセンタイル：0.00(Chemistry, Physical)Understanding how compositional complexity influences electrocatalytic kinetics remains a major challenge in the design of multicomponent materials. The multifaceted interactions between constituent elements are able to obscure the factors governing kinetics of electrode processes. Here, we introduce a small compositional change to modulate the rate-determining step of the oxygen evolution reaction (OER) by tuning the binding energies of key intermediates. We combine advanced characterization, including 
electrochemical X-ray absorption spectroscopy, with first-principles calculations to demonstrate that the drastic enhancement in OER activity of MnFeNi-based materials is driven by synergistic interactions among the constituent elements. This enhancement stems from targeted modulation of intrinsic reaction pathways, shifting the rate-determining step via controlled stabilization of key intermediates. Our findings introduce a clear viewpoint for understanding how compositional tuning governs kinetics in complex electrocatalytic systems, offering new design principles for next-generation electrochemical materials.
山根 結太*; 中根 丈太郎*; 荒木 康史; 家田 淳一
Physical Review B, 113(1), p.014421_1 - 014421_7, 2026/01
被引用回数：0 パーセンタイル：0.00(Materials Science, Multidisciplinary)We theoretically investigate emergent impedance induced by domain-wall dynamics in antiferromagnets. Emergent impedance, arising from a combined action of spin-transfer torque and spinmotive force, was previously predicted and observed in spiral magnets. Here we develop a formalism for the electrical response of an antiferromagnetic domain wall under ac currents, and obtain analytical expressions for the resulting emergent impedance. We find that two dynamical modes play separate roles in the emergent impedance: Translational motion of the domain-wall center generates a contribution proportional to its velocity, analogous to that arising from the corresponding motion of a spiral magnet. Another contribution, unique to antiferromagnetic domain walls, originates from the time-dependent canting of the sublattice magnetizations localized within the moving domain wall, whose magnitude is inversely proportional to the antiferromagnetic exchange coupling constant. The competition between these two distinct contributions determines the sign and magnitude of the imaginary part of the emergent impedance at sub-resonant frequencies. Our results provide a fundamental insight into electron transport in antiferromagnets, and open avenues for novel antiferromagnet-based spintronics devices.
H studied by 
Fe nuclear resonant inelastic scattering河智 史郎*; 平賀 晴弘*; 山浦 淳一*; 飯村 壮史*; 中村 博樹; 筒井 智嗣*; 依田 芳卓*; 町田 昌彦; 細野 秀雄*; 小林 寿夫*
Physical Review B, 113(2), p.024519_1 - 024519_7, 2026/01
被引用回数：0LaFeAsOH (
)の高濃度水素化物イオン置換領域における鉄のフォノンダイナミクスを調べるため、Fe核共鳴非弾性散乱測定を、超伝導および反強磁性の基底状態をそれぞれ示す
と0.51の2種類の多結晶試料に対して、5
300Kの広い温度範囲で実施した。得られた非弾性散乱スペクトルは、両組成間に顕著な差異を示した。Feのフォノン状態密度(PDOS)は、では15meVに顕著なピークを示す一方、
ではこのピークが消失している。密度汎関数理論(DFT)計算により、この15meVのPDOSピークはAs原子を介した最近接方向に沿ったFe原子の光学振動モードに関連していることが支持された。さらに計算は、で15meVのPDOSピークが抑制される原因が面内の電子的不等価性に起因することを示唆している。これらの結果は、磁気および構造秩序を示す組成では、広い温度範囲にわたり電子ネマティシティの兆候が持続する可能性がある一方、超伝導を示す組成ではその兆候がほとんど存在しないことを示唆している。
Fe
O
Lenander, E. Y.*; Nielsen, F. B.*; Lass, J.*; Hansen, U. B.*; Krighaar, K. M. L.*; Preuss, A.*; Weber, T.*; Enderle, M.*; Jacobsen, H.*; Stuhr, U.*; et al.
Physical Review B, 113(1), p.014424_1 - 014424_14, 2026/01
被引用回数：0The frustrated magnet BiFeO has been reported to exhibit complex spin dynamics coexisting with conventional spin wave excitations. The magnetic Fe
(
) ions are arranged into a distorted two-dimensional Cairo pentagonal lattice with weak couplings between the layers, developing long-ranged noncollinear antiferromagnetic order below 245 K. In order to enable studies and modeling of the complex dynamics close to 
, we have reexamined the magnetic excitations across the complete energy scale (
meV) at 10 K. We discover two distinct gaps, which can be explained by introducing, respectively, easy axis and easy plane anisotropy on the two unequivalent Fe sites. We develop a refined spin Hamiltonian that accurately accounts for the dispersion of essentially all spin-wave branches across the full spectral range, except around 40 meV, where a splitting and dispersion are observed. Polarization analysis shows that the system has magnetic anisotropic fluctuations, consistent with our model. A continuum of scattering is observed above the spin wave branches and is found to principally be explained by an instrumental resolution effect. The full experimental mapping of the excitation spectrum and the refined spin Hamiltonian provides a foundation for future quantitative studies of spin waves coexisting with unconventional magnetic fluctuations in this frustrated magnet found at higher temperatures.
Na inside the 
island of inversionSalinas, R.*; 岩崎 弘典*; 宇都野 穣; 他18名*
Physical Review C, 113(1), p.014330_1 - 014330_9, 2026/01
被引用回数：0中性子過剰核では中性子数20の魔法数が消滅していることが知られているが、それを特徴づける物理量が核変形に直接関係する
値である。この研究では、ミシガン州立大学のサイクロトロンにてNaのクーロン励起によってこれらの原子核の基底状態バンド間の値を測定した。
Naについては
と
、
Naについては
と
のそれぞれ2本の励起状態への値が得られ、大きな固有四重極モーメントをもった変形核であることが確かめられた。これらの実験値は殻模型による計算値ともよい一致を示している。
-wave 
baryonsSu, N.*; Chen, H.-X.*; Gubler, P.; 保坂 淳
Physical Review D, 113(1), p.016005_1 - 016005_7, 2026/01
被引用回数：1Using the QCD sum rule method, we investigate the mass splitting for the spin-orbit partner states of the 
baryon assuming that it is a -wave excitation with 
. This study is an extension of a previous work, in which the masses of these states were estimated with uncertainties too large to extract the reliable mass splitting. In the present study, by directly formulating a sum rule for the mass splitting, we obtain an improved prediction, 
MeV. This result provides a more quantitative insight into the spectrum of -wave baryons and serves as a useful reference for future experiments.
quartz irradiated with swift heavy ions; Thickness and edge effects石川 法人; 田口 富嗣*; 小河 浩晃; Toimil-Molares, M. E.*; Trautmann, C.*
Physical Review Materials (Internet), 10(1), p.016001_1 - 016001_7, 2026/01
被引用回数：0結晶性SiO(石英)試料に1.64GeVおよび200MeVのAuイオンを照射し、イオントラック形成に由来する照射誘起ナノ構造を透過型電子顕微鏡(TEM)を用いて調査した。解析の結果、通常観察される均一な非晶質イオントラックだけでなく、同心円状のコア-ハロー構造(イオン飛跡に沿った低密度コアとハロー損傷領域)を持つトラックも観察された。後者のタイプのトラックは、厚さが50nm未満の薄い試料領域でのみ確認され、こうした低密度コアを持つトラックの形成には薄い試料が必要条件であることが示唆された。さらに、試料端部ではクレーター状の構造を持つピット状トラックも確認された。表面を含む試料の形態が、複雑なナノ構造の形状に影響を与えていることが強く示唆された。これらの結果について、電子スパッタリングなどの表面現象や、試料の厚さおよび試料端効果の観点から議論した。
Malatesta, L. C.*; 末岡 茂; Wei
, N.-M.*; Gailleton, B.*; 塚本 すみ子*; 石村 大輔*; 高橋 直也*; 西村 卓也*; 片岡 香子*; 小松 哲也; et al.
Geophysical Research Letters, 52(24), p.e2025GL116602_1 - e2025GL116602_10, 2025/12
被引用回数：0 パーセンタイル：0.00(Geosciences, Multidisciplinary)The eastern margin of the Sea of Japan is a zone of great seismic and tsunami hazard due to multiple offshore and nearshore reverse faults as shown by the 2024 Mw7.5 Noto Peninsula Earthquake. Here we compare coseismic deformation of the 2024 Noto Peninsula Earthquake with 4,767 individual marine terraces attributed to 16 successive sea-level stages over the last Myr. This reveals that the earthquake faults started slipping between 326 and 238 ka. The emerged landscape is still adjusting to it while nearshore underwater scarps mark the active faults. Applied to nearby Sado Island, these observations reveal the likely location of an active fault that drives its fast deformation. Active faults defining the edge of uplifting land are likely found in the near shore domain, drowned by the current sea-level high stand.
和田 有希*; Wu, T.*; 鴨川 仁*; Wang, D.*; 岡田 豪*; 南斗 秀仁*; 澤野 達也*; 久保 守*; 米徳 大輔*; Diniz, G. Z.*; et al.
Journal of Geophysical Research; Atmospheres, 130(24), p.e2025JD043927_1 - e2025JD043927_16, 2025/12
被引用回数：0 パーセンタイル：0.00(Meteorology & Atmospheric Sciences)We report two gamma-ray glows observed on December 22, 2023, during a winter thunderstorm in Japan, using an array of four radiation detectors. The first glow, detected by one sensor, was quenched by a lightning discharge. The second glow appeared 2-3 minutes later and was tracked by three other detectors. Radar observations suggest both glows originated from the same thundercloud cell. However, the detection timing of the second glow was inconsistent with simple thundercloud movement, indicating temporal variations in intrinsic glow brightness. A three-dimensional lightning mapping observation suggests that a discharge activity depleted the electric field that generated the first glow, and that the electric field having produced the second glow has been rapidly recovered. In addition, the radar observations also detected a descent of the thundercloud core between the two glows, which may have developed an electrified region and the second glow enough to be observed by the detectors. Tracking gamma-ray glows is crucial for understanding electrified regions in thunderclouds and associated gamma-ray glows.
=1/2 Ising-like antiferromagnetic chain CsCoCl in transverse magnetic fields木村 尚次郎*; 大西 弘明; 鳴海 康雄*; 奥西 巧一*; 萩原 政幸*; 金道 浩一*; 菊池 彦光*
Journal of the Physical Society of Japan, 94(12), p.124703_1 - 124703_8, 2025/12
被引用回数：0 パーセンタイル：0.00(Physics, Multidisciplinary)We have performed high-field electron spin resonance (ESR) measurements on the =1/2 Ising-like one-dimensional (1D) antiferromagnet CsCoCl in the frequency range up to 3.1 THz and magnetic fields for 
up to 53 T, as well as density-matrix renormalization group (DMRG) calculations. The analysis of the high-field magnetization confirms that the quantum critical point in the transverse field is 
= 60.3 T. The results of the ESR measurements suggest the remarkable behavior that all the excitation branches coming from the Zeeman ladder converge to upon increasing the transverse fields. The ESR measurements with polarized electromagnetic waves show that the ESR absorption lines show clear polarization dependence. The absorption lines, which become soft in the transverse field, are revealed to couple with the magnetic field oscillating parallel to the static magnetic fields. These experimental results are compared with the detailed DMRG calculations.
清水 悠晴*; 橘高 俊一郎*; 河野 洋平*; 中村 翔太*; 芳賀 芳範; 山本 悦嗣; 町田 一成*; 網塚 浩*; 榊原 俊朗*
Physical Review B, 112(24), p.245157_1 - 245157_10, 2025/12
被引用回数：0 パーセンタイル：0.00(Materials Science, Multidisciplinary)We report the results of high-resolution dc magnetization and specific heat measurements on the unconventional superconductor UBe.Suppression of the non-Fermi-liquid behavior under field and a nontrivial fifth-order magnetic susceptibility were observed at low temperatures, suggesting the Fermi-surface reconstruction accompanying the crossover from non-Fermi-liquid to Fermi-liquid state in UBe.
Ou-Yang, Z.-X.*; Gubler, P.; 岡 眞*; Wang, G.-J.*; Wu, J.-J.*
Physical Review D, 112(11), p.114034_1 - 114034_13, 2025/12
被引用回数：0 パーセンタイル：0.00(Astronomy & Astrophysics)We propose an extension of the QCD sum rules, termed the resonance sum rules, to access resonance poles in the complex energy plane. By strategically introducing a contour in the complex plane and conformal mapping, the method intends to reach resonance poles on the second Riemann sheet. To validate this approach, we apply resonance sum rules to the square-well potential model, for which the pole locations are known. The analysis demonstrates a successful extraction of the pole positions and residues for both the S-wave and P-wave resonances. The results are in good agreement with the analytic solutions, with discrepancies within 5% for the pole positions and 20% for the residues. This framework provides a basis for future applications to realistic hadronic resonances, promising new insights into spectral properties of QCD.
篠原 佑也*; 岩下 拓哉*; 中西 真大*; Liu, Y.*; Cooper, V. R.*; 古府 麻衣子*; 楡井 真実; Dmowski, W.*; Hickner, M. A.*; 江上 毅*
Journal of Physical Chemistry B, 129(47), p.12330 - 12337, 2025/11
被引用回数：0 パーセンタイル：0.00(Biophysics)Enhancing proton transport in polymer electrolytes is crucial for advancing next-generation solid-state batteries, yet our understanding of proton conductivity in nonaqueous environments remains limited due to a lack of atomic-scale insights. In this study, we investigated the atomic-scale dynamics of 1,2,3-triazole, a small molecule capable of dynamic hydrogen bonding, as a model system for proton hopping in nonaqueous environments. Using the real-space correlation function determined by the double Fourier transformation of inelastic neutron scattering spectra, we identified that the self-motion of protons and intermolecular dynamics occur on comparable time scales. Furthermore, we observed that the activation energy associated with the intermolecular dynamics matches the energy barrier for molecular rotations determined through Density Functional Theory calculations. These findings underscore the importance of controlling molecular dynamics at the atomic scale to control proton transport. Additionally, we demonstrated that intermolecular dynamics in systems involving protons can be studied using inelastic neutron scattering even without deuteration, thereby providing a broader avenue for studying atomic-scale dynamics in soft matter systems.
