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-MgAgSbLi, J.*; Li, X.*; Zhang, Y.*; Zhu, J.*; Zhao, E.*; 古府 麻衣子; 中島 健次; Avdeev, M.*; Liu, P.-F.*; Sui, J.*; et al.
Applied Physics Reviews (Internet), 11(1), p.011406_1 - 011406_8, 2024/03
被引用回数：0 パーセンタイル：0.01(Physics, Applied)The desire for intrinsically low lattice thermal conductivity (
) in thermoelectrics motivates numerous efforts on understanding the microscopic mechanisms of heat transport in solids. Here, based on theoretical calculations, we demonstrate that -MgAgSb hosts low-energy localized phonon bands and avoided crossing of the rattler modes, which coincides with the inelastic neutron scattering result. Using the two-channel lattice dynamical approach, we find, besides the conventional contribution (
70% at 300 K) from particlelike phonons propagating, the coherence contribution dominated by the wavelike tunneling of phonons accounts for 30% of total at 300 K. By considering dual contributions, our calculated room-temperature of 0.64 Wm
K well agrees with the experimental value of 0.63 WmK. More importantly, our computations give a nonstandard 
dependence, perfectly explaining the abnormal temperature-trend of 
in experiment for -MgAgSb. By molecular dynamics simulation, we reveal that the structure simultaneously has soft crystalline sublattices with the metavalent bonding and fluctuating liquid-like sublattices with thermally induced large amplitude vibrations. These diverse forms of chemical bonding arouse mixed part-crystal part-liquid state, scatter strongly heat-carrying phonons, and finally produce extremely low . The fundamental research from this study will accelerate the design of ultralow- materials for energy-conversion applications.
neutron diffractionZhou, Y.*; Song, W.*; Zhang, F.*; Wu, Y.*; Lei, Z.*; Jiao, M.*; Zhang, X.*; Dong, J.*; Zhang, Y.*; Yang, M.*; et al.
Journal of Alloys and Compounds, 971, p.172635_1 - 172635_7, 2024/01
被引用回数：0 パーセンタイル：0(Chemistry, Physical)The grain orientation-dependent lattice strain evolution of a (TiZrHfNb)
refractory high-entropy alloy (HEA) during tensile loading has been investigated using neutron diffraction. The equivalent strain-hardening rate of each of the primary 
-oriented grain families was found to be relatively low, manifesting the macroscopically weak work-hardening ability of such a body-centered cubic (BCC)-structured HEA. This finding is indicative of a dislocation planar slip mode that is confined in a few single-slip planes and leads to in-plane softening by high pile-up stresses.
Bao, S.*; Gu, Z.-L.*; Shangguan, Y.*; Huang, Z.*; Liao, J.*; Zhao, X.*; Zhang, B.*; Dong, Z.-Y.*; Wang, W.*; 梶本 亮一; et al.
Nature Communications (Internet), 14, p.6093_1 - 6093_9, 2023/09
被引用回数：1 パーセンタイル：61.99(Multidisciplinary Sciences)Magnon polarons are novel elementary excitations possessing hybrid magnonic and phononic signatures, and are responsible for many exotic spintronic and magnonic phenomena. Despite long-term sustained experimental efforts in chasing for magnon polarons, direct spectroscopic evidence of their existence is hardly observed. Here, we report the direct observation of magnon polarons using neutron spectroscopy on a multiferroic Fe
Mo
O
possessing strong magnon-phonon coupling. Specifically, below the magnetic ordering temperature, a gap opens at the nominal intersection of the original magnon and phonon bands, leading to two separated magnon-polaron bands. Each of the bands undergoes mixing, interconverting and reversing between its magnonic and phononic components. We attribute the formation of magnon polarons to the strong magnon-phonon coupling induced by Dzyaloshinskii-Moriya interaction. Intriguingly, we find that the band-inverted magnon polarons are topologically nontrivial. These results uncover exotic elementary excitations arising from the magnon-phonon coupling, and offer a new route to topological states by considering hybridizations between different types of fundamental excitations.
Esser, S. P.*; Rahlff, J.*; Zhao, W.*; Predl, M.*; Plewka, J.*; Sures, K.*; Wimmer, F.*; Lee, J.*; Adam, P. S.*; McGonigle, J.*; et al.
Nature Microbiology (Internet), 8(9), p.1619 - 1633, 2023/09
被引用回数：2 パーセンタイル：79.73(Microbiology)CRISPR-Cas systems defend prokaryotic cells from viruses, plasmids, and other mobile genetic elements. Capitalizing on multi-omics approaches, we show here that the CRISPR-Cas systems of uncultivated archaea also play an integral role in mitigating potentially detrimental interactions with episymbionts. A comprehensive analysis of CRISPR-Cas-based infection histories revealed that uncultivated deep-subsurface archaeal primary-producers defend themselves from archaeal episymbionts of the DPANN superphylum of archaea, some of which are known to fuse their membranes with their host. We show that host cells counter these attacks by deploying one of two CRISPR-Cas systems (type I-B and type III-A) to target and disrupt essential genes in the episymbiont. However, genome-scale modeling of metabolic interactions between two deep subsurface host-symbiont systems revealed that host cells also benefit from the symbionts via metabolic complementation. We speculate that populations of these uncultivated archaeal episymbionts are currently transitioning from a parasitic lifestyle to one of mutualism, as must have occurred in countless mutualistic systems known today. By expanding our analysis to thousands of archaeal genomes, we conclude that CRISPR-Cas mediated resistance to archaeal episymbiosis evolved independently in various archaeal lineages and may be a wide-spread evolutionary phenomenon.
BaCo(PO
)Sheng, J.*; Wang, L.*; Candini, A.*; Jiang, W.*; Huang, L.*; Xi, B.*; Zhao, J.*; Ge, H.*; Zhao, N.*; Fu, Y.*; et al.
Proceedings of the National Academy of Sciences of the United States of America, 119(51), p.e2211193119_1 - e2211193119_9, 2022/12
被引用回数：3 パーセンタイル：28(Multidisciplinary Sciences)Although considerable progress has been made in the theoretical understanding of the low-dimensional frustrated quantum magnets, experimental realizations of a well-established scaling analysis are still scarce. This is particularly true for the two-dimensional antiferromagnetic triangular lattices. Owing to the small exchange strength, the newly discovered compound NaBaCo(PO) provides a rare opportunity for clarifying the quantum criticality in an ideal triangular lattice with quantum spin S=1/2. In addition to the establishment of the complete phase diagrams, the spin Hamiltonian with a negligible interplane interaction has been determined through the spin wave dispersion in the polarized state, which is consistent with the observation of a two-dimensional quantum critical point with the Bose-Einstein condensation of diluted free bosons.
Wang, Q.*; Hu, Q.*; Zhao, C.*; Yang, X.*; Zhang, T.*; Ilavsky, J.*; Kuzmenko, I.*; Ma, B.*; 舘 幸男
International Journal of Coal Geology, 261, p.104093_1 - 104093_15, 2022/09
被引用回数：5 パーセンタイル：69.58(Energy & Fuels)To understanding the spatial heterogeneity of mineral and pore structure variations in fine-grained shale, microscale X-ray fluorescence (micro-XRF) mapping, (ultra-) small-angle X-ray scattering [(U)SAXS] and wide-angle X-ray scattering were applied for two samples from a piece of Eagle Ford Shale in South Texas. Thin section petrography and field emission-scanning electron microscopy, X-ray diffraction (XRD), total organic carbon, and pyrolysis were also utilized to investigate the potential spatial heterogeneity of pore types, mineral and organic matter compositions for both samples. Overall, the siliceous-carbonate mineral contents in these carbonate-rich Eagle Ford Shale vary between laminations at mm scales. By analyzing six selected sub-samples on each of two samples with X-ray scattering and XRD techniques, nm-sized pores are mainly interparticle ones in the higher calcite regions, where the porosity is also relatively lower, while the lower calcite regions consist of both interparticle and intraparticle pore types with higher porosity. Finally, the micro-XRF and (U)SAXS are combined to generate porosity distribution maps to provide more insights about its heterogeneity related to the laminations and fractures at our observational scales.
; 
SR studies and charge-spin percolation modelSheng, Q.*; 金子 竜也*; Yamakawa, Kohtaro*; Guguchia, Z.*; Gong, Z.*; Zhao, G.*; Dai, G.*; Jin, C.*; Guo, S.*; Fu, L.*; et al.
Physical Review Research (Internet), 4(3), p.033172_1 - 033172_14, 2022/09
A pyrite system NiS
Se
exhibits a bandwidth controlled Mott transition via (S,Se) substitutions in a two-step process: the antiferromagnetic insulator (AFI) to antiferromagnetic metal (AFM) transition at 
0.45 followed by the AFM to paramagnetic metal (PMM) transition at 1.0. Among a few other Mott systems which exhibit similar two-step transitions, Ni(S,Se) is of particular interest because a large intermediate AFM region in the phase diagram would provide unique opportunities to study the interplay between the spin and charge order. By comparing and combining our muon spin relaxation studies and previous neutron scattering studies, here we propose a picture where the spin order is maintained by the percolation of "nonmetallic" localized and dangling Ni moments surrounded by S, while the charge transition from AFI to AFM is caused by the percolation of the conducting paths generated by the Ni-Se-Ni bonds.
K(Zn
Mn
)As studied by X-ray magnetic circular dichroism and resonant inelastic X-ray scattering鈴木 博人*; Zhao, G.*; 岡本 淳*; 坂本 祥哉*; Chen, Z.-Y.*; 野中 洋亮*; 芝田 悟朗; Zhao, K.*; Chen, B.*; Wu, W.-B.*; et al.
Journal of the Physical Society of Japan, 91(6), p.064710_1 - 064710_5, 2022/06
被引用回数：0 パーセンタイル：0(Physics, Multidisciplinary)The magnetic properties and the electronic excitations of the new diluted magnetic semiconductor BaK(ZnMn)As have been studied by X-ray magnetic circular dichroism (XMCD) and resonant inelastic X-ray scattering (RIXS). The sum rule analysis of the XMCD spectra indicates that the Mn atoms are in the high-spin configurations of 
, whereas the presence of competing ferromagnetic and antiferromagnetic interactions between the Mn ions reduces the net spin moment. Based on a comparison of the RIXS line shapes with those of GaMnAs, it is concluded that the ground state of Mn in BaK(ZnMn)As consists of both the 
and 
electron configurations.
Zhao, Y.*; Suzuki, T.*; Iimori, T.*; Kim, H.-W.*; Ahn, J. R.*; 堀尾 眞史*; 佐藤 祐輔*; 深谷 有喜; Kanai, T.*; Okazaki, K.*; et al.
Physical Review B, 105(11), p.115304_1 - 115304_8, 2022/03
被引用回数：1 パーセンタイル：17.38(Materials Science, Multidisciplinary)本研究では、時間・角度分解光電子分光を用いて、SiC基板上に作製したグラフェン層におけるキャリアダイナミクスについて調べた。光ポンピング後の準結晶グラフェンのディラックバンドでは、電子ドーピングに層依存性が観測された。また、光誘起キャリア輸送量は基板からの距離に依存することがわかった。フラット基板及びステップ基板上の単層グラフェンの結果から、キャリアの生成源は界面のステップ状態に由来することがわかった。本メカニズムは、密度汎関数計算による電子構造を基にした動的モデルにより記述できる。
Yang, J.*; Ren, W.*; Zhao, X.*; 菊地 龍弥*; Miao, P.*; 中島 健次; Li, B.*; Zhang, Z.*
Journal of Materials Science & Technology, 99, p.55 - 60, 2022/02
被引用回数：5 パーセンタイル：41.35(Materials Science, Multidisciplinary)物性測定と中性子散乱を組み合わせることにより、面心立方高エントロピー合金CrMnFeCoNiの磁気および熱輸送特性を調べた。DCおよびAC帯磁率は、温度領域全体で反強磁性および強磁性相互作用が共存する常磁性挙動を示し、それぞれ、常磁性から反強磁性への遷移、反強磁性から強磁性への遷移、およびスピン凍結に対応して、約80, 50、および20Kで3つの異常が見られる。電気伝導率と熱伝導率はNiに比べて大幅に低下しており、格子熱伝導率の温度依存性はガラスのようなプラトーを示す。非弾性中性子散乱測定は弱い非調和性を示唆し、熱輸送は欠陥散乱によって支配されると思われる。
CuTeO
Shangguan, Y.*; Bao, S.*; Dong, Z.-Y.*; Cai, Z.*; Wang, W.*; Huang, Z.*; Ma, Z.*; Liao, J.*; Zhao, X.*; 梶本 亮一; et al.
Physical Review B, 104(22), p.224430_1 - 224430_8, 2021/12
被引用回数：1 パーセンタイル：7.92(Materials Science, Multidisciplinary)Dimerized magnets forming alternating Heisenberg chains exhibit quantum coherence and entanglement and thus can find potential applications in quantum information and computation. However, magnetic systems typically undergo thermal decoherence at finite temperatures. Here, we show inelastic neutron scattering results on an alternating antiferromagnetic-ferromagnetic chain compound NaCuTeO that the excited quasiparticles can counter thermal decoherence and maintain strong correlations at elevated temperatures. At low temperatures, we observe clear dispersive singlet-triplet excitations arising from the dimers formed along the crystalline 
-axis. The excitation gap is of 18 meV and the bandwidth is about half of the gap. The band top energy has a weak modulation along the [100] direction, indicative of a small interchain coupling. The gap increases while the bandwidth decreases with increasing temperature, leading to a strong reduction in the available phase space for the triplons. As a result, the Lorentzian-type energy broadening becomes highly asymmetric as the temperature is raised. These results are associated with a strongly correlated state resulting from hard-core constraint and quasiparticle interactions. We consider these results to be not only evidence for strong correlations at finite temperatures in NaCuTeO, but also for the universality of the strongly correlated state in a broad range of quantum magnetic systems.
深谷 有喜; Zhao, Y.*; Kim, H.-W.*; Ahn, J.-R.*; 吹留 博一*; 松田 巌*
Physical Review B, 104(18), p.L180202_1 - L180202_5, 2021/11
被引用回数：10 パーセンタイル：69.8(Materials Science, Multidisciplinary)2層グラフェンはねじれ角に応じて多彩な物性を発現する。30
のねじれ角を持つ2層グラフェンでは、相対論的ディラックフェルミオンを有する二次元準結晶となる。本研究では、陽電子回折を用いて、SiC(0001)基板上に合成したグラフェン準結晶の原子配置を解明した。グラフェン準結晶の層間隔は3.46
であり、通常のAB積層型に比べ0.17広がることがわかった。この値は、グラフェン間のカップリングの強さを決定するうえで重要なパラメーターとなる。
Hao, Y. Q.*; Wo, H. L.*; Gu, Y. M.*; Zhang, X. W.*; Gu, Y. Q.*; Zheng, S. Y.*; Zhao, Y.*; Xu, G. Y.*; Lynn, J. W.*; 中島 健次; et al.
Science China; Physics, Mechanics & Astronomy, 64(3), p.237411_1 - 237411_6, 2021/03
被引用回数：6 パーセンタイル：61.42(Physics, Multidisciplinary)We report thermodynamic and neutron diffraction measurements on the magnetic ordering properties of the honeycomb lattice magnet YbCl. We find YbCl exhibits a N
el type long-range magnetic order at the wavevector (0, 0, 0) below T
= 600 mK. This magnetic order is associated with a small sharp peak in heat capacity and most magnetic entropy release occurs above the magnetic ordering temperature. The magnetic moment lies in-plane, parallel to the monoclinic a-axis, whose magnitude m
= 0.86(3) 
is considerably smaller than the expected fully ordered moment of 2.24 for the doublet crystal-field ground state. The magnetic ordering moment gradually increases with increasing magnetic field perpendicular to the ab-plane, reaching a maximum value of 1.6(2) at 4 T, before it is completely suppressed above 9 T. These results indicate the presence of strong quantum fluctuations in YbCl.
Wang, Y.*; Jia, G.*; Cui, X.*; Zhao, X.*; Zhang, Q.*; Gu, L.*; Zheng, L.*; Li, L. H.*; Wu, Q.*; Singh, D. J.*; et al.
Chem, 7(2), p.436 - 449, 2021/02
被引用回数：194 パーセンタイル：99.8(Chemistry, Multidisciplinary)Nanozymes are promising alternatives to natural enzymes, but their use remains limited owing to poor specificity. Overcoming this is extremely challenging due to the intrinsic structural complexity of these systems. We report theoretical design and experimental realization of a series of heterogeneous molybdenum single-atom nanozymes (named Mo
-N
-C), wherein we find that the peroxidase-like specificity is well regulated by the coordination numbers of single Mo sites. The resulting Mo-N-C catalyst shows exclusive peroxidase-like behavior. It achieves this behavior via a homolytic pathway, whereas Mo-N-C and Mo-N-C catalysts have a different heterolytic pathway. The mechanism of this coordination-number-dependent enzymatic specificity is attributed to geometrical structure differences and orientation relationships of the frontier molecular orbitals.
He, H.*; Naeem, M.*; Zhang, F.*; Zhao, Y.*; Harjo, S.; 川崎 卓郎; Wang, B.*; Wu, X.*; Lan, S.*; Wu, Z.*; et al.
Nano Letters, 21(3), p.1419 - 1426, 2021/02
被引用回数：41 パーセンタイル：95.34(Chemistry, Multidisciplinary)In CrCoNi, a so-called medium-entropy alloy, an fcc-to-hcp phase transformation has long been anticipated. Here, we report an in situ loading study with neutron diffraction, which revealed a bulk fcc-to-hcp phase transformation in CrCoNi at 15 K under tensile loading. By correlating deformation characteristics of the fcc phase with the development of the hcp phase, it is shown that the nucleation of the hcp phase was triggered by intrinsic stacking faults. The confirmation of a bulk phase transformation adds to the myriads of deformation mechanisms available in CrCoNi, which together underpin the unusually large ductility at low temperatures.
Guo, J.*; Zhao, X.*; 河村 聖子; Ling, L.*; Wang, J.*; He, L.*; 中島 健次; Li, B.*; Zhang, Z.*
Physical Review Materials (Internet), 4(6), p.064410_1 - 064410_7, 2020/06
被引用回数：10 パーセンタイル：48.03(Materials Science, Multidisciplinary)NaYbO has been reported as a possible host for the quantum spin-liquid state. Here, the composition-dependent polycrystalline NaYbO (
, 0.03, and 0.07) has been investigated by combining high-field magnetizations and inelastic neutron scattering techniques. For the sample, no signature of a magnetic order is observed down to 0.3 K. Inelastic neutron scattering measurement suggests a continuous low-energy excitation spectrum centered at momentum transfer 
~
and extending up to energy transfer 
~meV. In contrast, 
and 0.07 samples exhibit magnetic transitions at 1.1 and 2.3 K, respectively. High-field magnetization measurements indicate similar behaviors for and 0.03 samples including plateau-like features at the 1/3 saturated magnetization, which implies that the spin disorder in the sample might be suppressed preceding the emergence of the up-up-down phase. This composition- and field-dependent study allows us to construct complete phase diagrams indicating that NaYbO is a promising candidate for the quantum spin-liquid state in close proximity to the antiferromagnetic instability tuned by the application of magnetic fields as well as controlling the concentration of Na
ion vacancies.
-MgAgSbLi, X.*; Liu, P.-F.*; Zhao, E.*; Zhang, Z.*; Guide, T.*; Le, M. D.*; Avdeev, M.*; 池田 一貴*; 大友 季哉*; 古府 麻衣子; et al.
Nature Communications (Internet), 11, p.942_1 - 942_9, 2020/02
被引用回数：36 パーセンタイル：90.35(Multidisciplinary Sciences)高性能の熱電材料実現には低熱伝導率が必要であり、その機構としてはフォノンの非調和によるもの、あるいは、結晶構造の動的な乱れによるフォノンの散乱によるものがあげられ、どちらも中性子散乱でその現象が明らかにされている。我々は中性子散乱と第一原理計算を組み合わせ、-MgAgSbにおいて、静的な結晶構造の乱れとフォノンの非調和性が組み合わされて極端に低い熱伝導率が実現されているということを見いだしたので、これを報告する。
GeWo, H.*; Wang, Q.*; Shen, Y.*; Zhang, X.*; Hao, Y.*; Feng, Y.*; Shen, S.*; He, Z.*; Pan, B.*; Wang, W.*; et al.
Physical Review Letters, 122(21), p.217003_1 - 217003_5, 2019/05
被引用回数：5 パーセンタイル：42.69(Physics, Multidisciplinary)We report neutron scattering measurements of single-crystalline YFeGe in the normal state, which has the same crystal structure as the 122 family of iron pnictide superconductors. YFeGe does not exhibit long-range magnetic order but exhibits strong spin fluctuations. Like the iron pnictides, YFeGe displays anisotropic stripe-type antiferromagnetic spin fluctuations at (
). More interesting, however, is the observation of strong spin fluctuations at the in-plane ferromagnetic wave vector (
). These ferromagnetic spin fluctuations are isotropic in the (
) plane, whose intensity exceeds that of stripe spin fluctuations. Both the ferromagnetic and stripe spin fluctuations remain gapless down to the lowest measured energies. Our results naturally explain the absence of magnetic order in YFeGe and also imply that the ferromagnetic correlations may be a key ingredient for iron-based materials.
Yin, H.*; Chung, B.*; Chen, F.*; 大内 隆成*; Zhao, J.*; 田中 伸幸; Sadoway, D. R.*
Nature Energy (Internet), 3(2), p.127 - 131, 2018/02
被引用回数：55 パーセンタイル：87.54(Energy & Fuels)リチウムイオン選択性を有する多孔質伝導膜を用い、正極と負極の電極金属を分離することで、性能劣化が小さく、高い充放電効率が得られるこれまでにない概念の溶融塩蓄電池の開発を行った。多孔質伝導膜にセラミックスの窒化チタン焼結体を、正・負極材に、それぞれ鉛及びリチウム鉛を使用した蓄電池を作製し、作動温度410Cにおける100サイクル試験を行った。初期の100サイクル平均の性能で、充放電効率が90%以上と優れた性能を達成するとともに、その間の充放電効率の低下速度は1サイクル当たり0.0017%が得られた。これは10年経過後も充放電効率の劣化は10%以下と高寿命であることを示している。また、多孔質状金属(ステンレス及びチタン)に窒化チタンをコーティングした多孔質伝導膜を使用した場合においても、同様の充放電効率を示すことを明らかにした。このように本開発で導入した金属を基盤とする多孔質伝導膜は、低電気抵抗が可能な薄膜化かつ工業的スケールアップに向けた大型化が期待できるものである。
TAs (
= Co,Ni)Tam, D. M.*; Song, Y.*; Man, H.*; Cheung, S. C.*; Yin, Z.*; Lu, X.*; Wang, W.*; Frandsen, B. A.*; Liu, L.*; Gong, Z.*; et al.
Physical Review B, 95(6), p.060505_1 - 060505_6, 2017/02
被引用回数：23 パーセンタイル：71.49(Materials Science, Multidisciplinary)We use neutron diffraction and muon spin relaxation to study the effect of in-plane uniaxial pressure on the antiferromagnetic (AF) orthorhombic phase in BaFeTAs and its Co- and Ni-substituted members near optimal superconductivity. In the low-temperature AF ordered state, uniaxial pressure necessary to detwin the orthorhombic crystals also increases the magnetic ordered moment, reaching an 11% increase under 40 MPa for BaFe
Co
As, and a 15% increase for BaFe
Ni
As. We also observe an increase of the AF ordering temperature (
) of about 0.25 K/MPa in all compounds, consistent with density functional theory calculations that reveal better Fermi surface nesting for itinerant electrons under uniaxial pressure. The doping dependence of the magnetic ordered moment is captured by combining dynamical mean field theory with density functional theory, suggesting that the pressure-induced moment increase near optimal superconductivity is closely related to quantum fluctuations and the nearby electronic nematic phase.
