検索対象:     
報告書番号:
※ 半角英数字
 年 ~ 
 年
検索結果: 1106 件中 1件目~20件目を表示

発表形式

Initialising ...

選択項目を絞り込む

掲載資料名

Initialising ...

発表会議名

Initialising ...

筆頭著者名

Initialising ...

キーワード

Initialising ...

発表言語

Initialising ...

発行年

Initialising ...

開催年

Initialising ...

選択した検索結果をダウンロード

論文

Revisiting $$^{9}$$Be nuclear magnetic resonance in UBe$$_{13}$$; Itinerant-localized duality and possible Fermi surface reconstruction at high magnetic field

松木 麟太朗*; 南 晶子*; 小手川 恒*; 播磨 尚朝*; 芳賀 芳範; 山本 悦嗣; 大貫 惇睦*; 藤 秀樹*

Journal of the Physical Society of Japan, 94(12), p.124702_1 - 124702_8, 2025/11

We report on new results of $$^{9}$$Be nuclear magnetic resonance measurements conducted on a single crystal of the heavy fermion superconductor UBe$$_{13}$$. A comparison between the knight shift and the classical dipolar shift provides microscopic evidence for the nature of an itinerant-localized duality in UBe$$_{13}$$. Furthermore, a reconstruction of part of the multiple Fermi surfaces in the high-magnetic-field region is suggested.

論文

Metallization and pressure-induced superconductivity in carrier doped excitonic insulator (Ta$$_{1-x}$$Ti$$_x$$)$$_2$$NiSe$$_5$$

土田 駿*; 廣瀬 雄介; 関川 卓也; 大野 義章*; 平原 卓也*; 佐野 純佳*; 河口 彰吾*; 小林 慎太郎*; 上床 美也*; 摂待 力生*

Journal of the Physical Society of Japan, 94(11), p.114703_1 - 114703_7, 2025/10

本研究では、励起子絶縁体Ta$$_2$$NiSe$$_5$$へのキャリアドープ効果を調べるために、(Ta$$_{1-x}$$Ti$$_x$$)$$_2$$NiSe$$_5$$の単結晶合成し、電気抵抗$$rho$$ホール係数$$R_{rm H}$$およびバンド計算を行った。TaサイトのTi元素置換により、結晶構造は変化せず励起子絶縁体転移温度$$T_{rm c}$$は連続的に抑制され$$x$$=0.104で83Kまで抑制された。置換量$$x$$を増やしていくと、半導体的な$$rho$$$$R_{rm H}$$の低温での増大が著しく抑制され、$$x>0.06$$では金属的な振る舞いに変わることを見出し、励起子相関のある金属状態が実現されている可能性がある。この金属化はバンド計算により、キャリアドーピング効果によって説明できる。このキャリアドープ物質を加圧していくと、2.6GPa以上で超伝導となることを明らかにした。この圧力は母物質Ta$$_2$$NiSe$$_5$$の圧力誘起超伝導が現れる8GPaよりもはるかに小さく、Ti置換によるキャリアドープが超伝導に有利に働いたと考えられる。

論文

Hidden order state under uni-axial stress in URu$$_2$$Si$$_2$$

神戸 振作; 石飛 尊之; 播磨 尚朝*

Journal of the Physical Society of Japan, 94(10), p.104703_1 - 104703_5, 2025/10

[100]方向および[110]方向に沿った一軸応力下におけるURu$$_2$$Si$$_2$$の隠れた秩序状態の研究である。一軸応力下で誘起される空間群と秩序パラメータは、実験事実と群論的考察に基づいて推定される。一軸応力下での測定を用いて隠れた秩序の秩序パラメータを同定する手法を提案する。

論文

Upper limit for the $$^{248}$$Cm($$^{50}$$Ti,xn)$$^{298-x}$$Og reaction cross section

Gall, B. J.-P.*; 浅井 雅人; 伊藤 由太; 豊嶋 厚史*; 他30名*

Journal of the Physical Society of Japan, 94(9), p.094201_1 - 094201_9, 2025/09

 被引用回数:0 パーセンタイル:0.00

$$^{50}$$Tiビームを$$^{248}$$Cm標的に照射してOg同位体を探索する実験を理化学研究所の仁科加速器科学研究センターにて実施した。準弾性後方散乱の励起関数から導出した準弾性散乱障壁分布より最適ビームエネルギーを決定した。実験の結果、Og同位体の崩壊は見つからず、1事象検出断面積として0.27pb、1$$sigma$$信頼度の断面積上限値として0.50pbの値を見積もることができた。

論文

Plausible driving forces in elliptic droplet self-propulsion

井上 悠平*; 野々山 朋信*; Kang, Z.; 藪中 俊介; 津川 暁

Journal of the Physical Society of Japan, 94(9), p.094001_1 - 094001_6, 2025/09

 被引用回数:0 パーセンタイル:0.00

Particles that self-propel owing to changes in their own internal state are called self-propelled particles and are driven by the Marangoni effect caused by concentration and/or temperature gradients. As the propulsion speed increases, they become elliptically shaped. However, the driving forces behind this phenomenon are still not completely understood. Therefore, we used a numerical method to confirm whether elliptical deformation actually occurred in the self-propulsion of a droplet, and quantitatively confirmed how the surface tension of the droplet changed. As a result, we confirmed that the second mode of the surface tension was the driving force of the contour of the droplet. Furthermore, the competing combination of the fluid pressure gradient and Korteweg force associated with the reacting molecules was the actual driving force of the fluid that induced a self-organized flow.

論文

Surface structure and surface state of a tight-binding model on a diamond lattice

久保 勝規

Journal of the Physical Society of Japan, 94(7), p.074701_1 - 074701_5, 2025/07

 被引用回数:0 パーセンタイル:0.00(Physics, Multidisciplinary)

Surface states of a tight-binding model with nearest-neighbor hopping on a diamond lattice of finite thickness are investigated. We consider systems with (001), (110), and (111) surfaces. Even if the surface direction is fixed, there is freedom to choose the surface structure due to the two-sublattice nature of a diamond lattice. The existence of surface states is governed by the topology of the matrix elements of the bulk Hamiltonian. In this sense, the existence of surface states is determined by the bulk Hamiltonian. However, the matrix elements depend on the choice of the unit cell, which should be chosen to conform to the surface structure. Thus, the surface states depend on the surface structure. We find that for each surface direction, there are two choices of surface structure, and depending on the chosen structure, the corresponding surface states emerge in distinct regions of the surface Brillouin zone.

論文

Influence of magnetic ordering on quasiparticle spectral functions; Comparison of electronic states of CeCu$$_6$$ and CeRu$$_2$$Ge$$_2$$

川崎 郁斗; 藤森 伸一; 山上 浩志; 松田 達磨*; 大貫 惇睦*

Journal of the Physical Society of Japan, 94(8), p.084702_1 - 084702_9, 2025/07

 被引用回数:0 パーセンタイル:0.00(Physics, Multidisciplinary)

The electronic state of CeCu$$_6$$, an archetypical heavy compound without long-range magnetic order, has been investigated by angle-resolved photoemission spectroscopy (ARPES) experiments using soft x rays. The Ce 3$$d$$-4$$f$$ resonant ARPES experiments have revealed the 4$$f$$ partial density of states consists of a quasiparticle band near the Fermi level ($$f^1$$ component) and an $$f^0$$ component, the latter of which is physically equivalent to the lower Hubbard band in the Hubbard model. The observed strong intensity of the $$f^0$$ component indicates that the quasiparticle band near the Fermi level is strongly renormalized by the electron correlation effect, consistent with the significantly enhanced electronic specific-heat coefficient of CeCu$$_6$$. We compare the present 3$$d$$-4$$f$$ resonant ARPES spectra of CeCu$$_6$$ with those for CeRu$$_2$$Ge$$_2$$, which has a low Kondo temperature similar to CeCu$$_6$$ but shows a ferromagnetic order. The results of this comparison suggest that the ferromagnetic correlation in CeRu$$_2$$Ge$$_2$$ seems to strongly suppress the degree of renormalization for the quasiparticle band. We also showed that the intensities of both the $$f^1$$ and $$f^0$$ components for CeCu$$_6$$ hardly depend on temperature.

論文

Superzone gap formation induced by ferroic orders

石飛 尊之

Journal of the Physical Society of Japan, 94(7), p.075001_1 - 075001_2, 2025/07

 被引用回数:0 パーセンタイル:64.72

We show that superzone gap formation-phenomena usually attributed to antiferroic ordering-can also arise from ferroic orders in materials featuring sublattice structures. Through an analysis of a $$p$$-orbital tight-binding model on a zigzag chain, we reveal that ferroquadrupolar or ferromagnetic ordering, as well as external magnetic fields, can generate a Su-Schrieffer-Heeger-type gap.

論文

Successive phase transitions in the quasi-kagome lattice system URhSn studied by resonant X-ray scattering

田端 千紘; 今 布咲子*; 日比野 瑠央*; 清水 悠晴*; 網塚 浩*; 金子 耕士; 本間 佳哉*; 青木 大*; 中尾 裕則*

Journal of the Physical Society of Japan, 94(8), p.083701_1 - 083701_5, 2025/07

 被引用回数:1 パーセンタイル:64.72(Physics, Multidisciplinary)

Resonant X-ray scattering at the uranium M4 edge revealed successive phase transitions in URhSn. An antiferro-quadrupole (AFQ) order with propagation vector q = 0 emerges between 16 K and 54 K. Below 16 K, this AFQ order coexists with a canted magnetism, leading to a ground state that breaks mirror symmetry and exhibits chirality or polarity.

論文

Distinguishing ion dynamics from muon diffusion in muon spin relaxation II; Extension to paramagnetic muons

門野 良典*; 伊藤 孝

Journal of the Physical Society of Japan, 94(6), p.064601_1 - 064601_11, 2025/06

 被引用回数:5 パーセンタイル:95.66(Physics, Multidisciplinary)

We extend the previously published model that distinguishes between the diffusive motion of diamagnetic muons and the dynamics of ions around the muon in matter, and propose a generalized model for $$paramagnetic$$ $$muons$$ (Mu$$^0$$s, bound states of a muon and an unpaired electron) observed in non-metallic host materials. The new model distinguishes among the independent motion of unpaired electron associated with Mu$$^0$$, the self-diffusive motion of Mu$$^0$$ as single atomic entity, and that of the ions surrounding Mu$$^0$$, where the muon spin relaxation is induced by dynamical fluctuations of the hyperfine (HF) field exerted from the unpaired electron (e.g., due to spin/charge exchange reaction) and/or that of the nuclear hyperfine (NHF) interactions between the unpaired electron and the surrounding ions. We have applied this model to the muonated radicals (Mu$$^0$$s in a polaron state) in conducting polymers, and examined the validity of the interpretations claimed in the earlier literature that the spin relaxation is induced by quasi-one dimensional jump motion of the unpaired electron. The result suggests that experimental support for such a claim is still inadequate and needs to be reexamined, including the possibility of other origins for the fluctuations. It is expected that our model will prove a useful guide for $$mu$$SR studies of various local dynamics involving paramagnetic muon states.

論文

Three-stage Phase Transitions and Field-induced Phases in CeCoSi; A Landau Theory

石飛 尊之

Journal of the Physical Society of Japan, 94(7), p.073703_1 - 073703_4, 2025/06

 被引用回数:0 パーセンタイル:75.00(Physics, Multidisciplinary)

We investigate both the nonmagnetic and magnetic ordered phases of CeCoSi using Landau theory. Our analysis predicts that three successive phase transitions occur at zero magnetic field. A quadrupole order parameter that emerges below $$T$$$$_{0}$$ = 12 K acts as a weak symmetry-breaking field on the antiferromagnetic ordering below $$T_{rm N}$$ = 9.4 K, giving rise to two-stage magnetic transitions. In the higher-temperature antiferromagnetic phase in the temperature range in $$T_{rm s2}$$ = 8 K $$<$$ $$T$$ $$<$$ $$T_{rm N}$$, an out-of-plane component of antiferromagnetic moment may be present or absent. If present, magnetic fields applied along the [100] and [110] directions induce additional magnetic phases.

論文

Flat surface state with octupole moment in an $$e_g$$ orbital system on a simple cubic lattice

久保 勝規

Journal of the Physical Society of Japan, 94(5), p.054703_1 - 054703_7, 2025/05

 被引用回数:6 パーセンタイル:96.81(Physics, Multidisciplinary)

A tight-binding model for $$e_g$$ orbitals on a simple cubic lattice with finite thickness is investigated. The hopping integrals for nearest-neighboring sites are considered. We examine the electronic band structures for systems with (001), (110), and (111) surfaces. Electronic states well localized around the surfaces are found for the (110) and (111) surfaces. In particular, the surface state is flat and extends in the entire Brillouin zone for the (111) surface, provided the bulk band projected onto the surface Brillouin zone is gapped. We also find that these surface states possess octupole moments in both the (110) and (111) surface cases.

論文

Neutron spectroscopy study on crystalline electric field excitations in NdB$$_4$$

山内 宏樹; 目時 直人; 綿貫 竜太*; Hong, T.*; Fernandez-Baca, J. A.*; 萩原 雅人; 益田 隆嗣*; 吉沢 英樹*; 伊藤 晋一*

Journal of the Physical Society of Japan, 94(5), p.054705_1 - 054705_8, 2025/04

 被引用回数:0 パーセンタイル:0.00(Physics, Multidisciplinary)

The $textit{f}$-electron states of NdB$$_4$$ were determined by observing crystalline electric field (CEF) excitations with inelastic neutron scattering experiments. Our analysis yields CEF excitation energies of 2.8, 12.4, 17.2, and 25.4 meV. The $textit{f}$-electron states are simply described by one of $$J$$-multiplets $$left|pm J_z rightrangle$$ with negligibly small mixing. The ground state is the pseudo-quartet consist of the ground doublet dominated by $$left|pm frac{5}{2} rightrangle$$ and the first excited doublet dominated by $$left|pm frac{7}{2} rightrangle$$ at 2.8 meV, which is consistent with magnetic specific heat and entropy reported in earlier study. The simple $textit{f}$-electron states in NdB$$_4$$ are the consequence of the strong uniaxial and in-plane isotropic CEF potential due to the local structure of Nd$$^{3+}$$ ions with point symmetry $$C_{2v}$$.

論文

Anisotropic magnetic field-temperature phase diagrams in CeCoSi

日高 宏之*; 柳谷 駿*; 小野寺 進太朗*; 柳澤 達也*; 網塚 浩*; 谷田 博司*; 石飛 尊之

Journal of the Physical Society of Japan, 94(3), p.034706_1 - 034706_9, 2025/03

 被引用回数:1 パーセンタイル:82.78(Physics, Multidisciplinary)

We investigated the magnetic-field direction anisotropy of the unknown ordered phase in the tetragonal compound CeCoSi through bulk physical property measurements. The anisotropy in the field direction, previously identified in X-ray diffraction experiments, where a field-induced phase appears along [100] but not along [110], was confirmed in the bulk properties. Combining these experimental results with Landau theory, we infer that the field-induced phase in the [100] direction emerges under an infinitesimally small magnetic field.

論文

The Influence of structural dynamics in two-dimensional hybrid organic-inorganic perovskites on their photoluminescence efficiency; Neutron scattering analysis

Rajeev, H. S.*; Hu, X.*; Chen, W.-L.*; Zhang, D.*; Chen, T.*; 古府 麻衣子*; 梶本 亮一; 中村 充孝; Chen, A. Z.*; Johnson, G. C.*; et al.

Journal of the Physical Society of Japan, 94(3), p.034602_1 - 034602_14, 2025/03

 被引用回数:1 パーセンタイル:64.72(Physics, Multidisciplinary)

Two-dimensional hybrid organic-inorganic perovskites (HOIPs) have emerged as promising materials for light-emitting diode applications. In this study, by using time-of-flight neutron spectroscopy we identified and quantitatively separated the lattice vibrational and molecular rotational dynamics of two perovskites, butylammonium lead iodide (BA)$$_{2}$$PbI$$_{4}$$ and phenethyl-ammonium lead iodide (PEA)$$_{2}$$PbI$$_{4}$$. By examining the corresponding temperature dependence, we found that the lattice vibrations, as evidenced by neutron spectra, are consistent with the lattice dynamics obtained from Raman scattering. We revealed that the rotational dynamics of organic molecules in these materials tend to suppress their photoluminescence quantum yield (PLQY) while the vibrational dynamics did not show predominant correlations with the same. Additionally, we observed photoluminescence emission peak splitting for both systems, which becomes prominent above certain critical temperatures where the suppression of PLQY begins. This study suggests that the rotational motions of polarized molecules may lead to a reduction in exciton binding energy or the breaking of degeneracy in exciton binding energy levels, enhancing non-radiative recombination rates, and consequently reducing photoluminescence yield. These findings offer a deeper understanding of fundamental interactions in 2D HOIPs and could guide the design of more efficient light-emitting materials for advanced technological applications.

論文

Two-dimensional Dresselhaus-type spin texture and nonreciprocal magnetoresistance in magnetic semiconductor EuIr$$_4$$In$$_2$$Ge$$_4$$

横山 旭*; 仲地 立*; 本間 佳哉*; 仲村 愛*; 清水 悠晴*; Li, D.*; 三宅 厚志*; 本多 史憲*; 青木 大*; 大貫 惇睦*; et al.

Journal of the Physical Society of Japan, 94(2), p.023701_1 - 023701_4, 2025/02

We present the nonreciprocal magnetoresistance (NRMR) and spin texture of the noncentrosymmetric magnetic semiconductor EuIr$$_4$$In$$_2$$Ge$$_4$$. Anisotropy measurements of NRMR for different crystalline axes under rotational magnetic fields revealed a two-dimensional Dresselhaus-type spin texture of this material, where the spin polarization is confined to the tetragonal (001) plane. Strong coupling between NRMR and magnetism was suggested by the low-temperature field dependence of NRMR; however, the magnitude of NRMR was more rapidly suppressed by increasing the temperature than that of magnetic susceptibility. This distinct behavior implies extra mechanisms to reduce the NRMR in addition to the reduction of magnetic moment due to the temperature increase.

論文

Electronic phase diagram of itinerant electron metamagnet UCoAl

前田 瑞穂*; 松田 達磨*; 芳賀 芳範; 白崎 謙次*; 木村 憲彰*

Journal of the Physical Society of Japan, 94(2), p.024707_1 - 024707_6, 2025/01

 被引用回数:0 パーセンタイル:0.00(Physics, Multidisciplinary)

We investigate the pressure dependence of the magnetoresistivity and Hall resistivity for an itinerant-electron metamagnet UCoAl. The first-order metamagnetic transition point varies as a function of hydrostatic pressure and terminates at the critical pressure 2.0 GPa. The electronic system, however, does not show criticality at this pressure but extends to higher pressures, unlike the usual quantum critical behavior.

論文

Self-learning Monte Carlo with equivariant Transformer

永井 佑紀; 富谷 昭夫*

Journal of the Physical Society of Japan, 93(11), p.114007_1 - 114007_8, 2024/11

 被引用回数:1 パーセンタイル:47.86(Physics, Multidisciplinary)

生成AIにおける基幹技術であるTransformerを用いた新しい自己学習モンテカルロ法を提案した。本研究では、文章における距離の離れた単語の関連性を推測することができるTransformerのAttention機構を用いることにより、電子系の相転移で重要となる長距離相関を効率よく取り込める有効模型を構築した。さらに、スピン回転、空間並進など系が満たすべき対称性をネットワークに取り込むことにより、パラメータ数を劇的に減らすことに成功した。また、レイヤー数を増やすにつれてlossが減っていくというスケーリング則を見出した。

論文

Clear reduction in spin susceptibility and superconducting spin rotation for $$H||a$$ in the early-stage sample of spin-triplet superconductor UTe$$_2$$

北川 俊作*; 徳永 陽; 酒井 宏典; 神戸 振作; 他11名*

Journal of the Physical Society of Japan, 93(12), p.123701_1 - 123701_5, 2024/11

 被引用回数:5 パーセンタイル:85.87(Physics, Multidisciplinary)

We report the re-measurement of the $$a$$-axis spin susceptibility component in an early-stage sample of the spin-triplet superconductor UTe$$_2$$ with the transition temperature of $$T_{rm SC}$$ = 1.6 K. Using Knight-shift measurements along the $$b$$ axis and at a 10-degree tilt from the $$b$$ axis towards the $$a$$ axis, we accurately determined the $$a$$-axis component without directly measuring the $$a$$-axis Knight shift. The experiment reveals that the previously reported absence of the reduction in Knight shift is attributed to the missing of signal from the superconducting region and to the detection of residual signals from the non-superconducting region instead.

論文

Atomic imaging of BaTiO$$_{3}$$ by multiple-wavelength neutron holography

山川 昂大*; 中田 肇*; 木村 耕治*; 及川 健一; 原田 正英; 稲村 泰弘; 大山 研司*; 林 好一*

Journal of the Physical Society of Japan, 93(10), p.104601_1 - 104601_5, 2024/10

 被引用回数:1 パーセンタイル:28.73(Physics, Multidisciplinary)

Atomic resolution holography is a method to obtain atomic arrangements around specific elements. In particular, neutron holography enables the observation of light elements such as O atoms, which are difficult to observe using X-rays. In this study, neutron holography experiments were conducted on BaTiO$$_{3}$$. As a result, clear atomic images of O surrounding Ti were successfully observed. Based on the calculation of image intensity as a function of atomic displacement, the displacement of the O atom relative to the Ti atom was estimated to be 0.23 $AA from the observed image intensity of the O atom. Furthermore, considering the atomic displacement parameter, the difference in position between the Ti and O atoms in the polarization direction was estimated to be 0.16{AA}$.

1106 件中 1件目~20件目を表示