物理学Physics

▲ 作者：DANIEL JOST, RESHAM BABU REGMI, EDER G. LOMELI, SAMUEL SAHEL-SCHACKIS, MONIKA SCHEUFELE, MARCEL NEUHAUS, ET AL.

▲ 链接：

https://www.science.org/doi/10.1126/science.adv3196

▲ 摘要：

交错磁性被认为是一种介于铁磁性和反铁磁性性质之间的磁性相。此类材料中观察到的动量依赖性自旋劈裂反映了其独特的对称性特征，而这些特征也为手性磁振子的出现创造了条件。

研究组提供了直接实验证据，通过圆二色共振非弹性X射线散射揭示了候选交错磁体碲化锰（MnTe）中存在手性磁振子。研究组将这一模式称为手性交错磁振子，其自旋极化表现出明显的动量依赖性，与MnTe的交错磁g波对称性一致。

该偏振分辨数据证实了一类离散磁激发的存在，展示了交错磁序如何塑造自旋动力学，并为自旋电子学和量子技术的进步奠定了基础。

▲ Abstract：

Altermagnetism has been recognized as a magnetic phase that bridges the properties of ferro- and antiferromagnetism. The momentum-dependent spin splitting observed in these materials reflects their distinctive symmetry characteristics, which also establish the conditions for chiral magnons to emerge. Here we provide direct experimental evidence for a chiral magnon in the altermagnetic candidate manganese telluride (MnTe) revealed by circular-dichroism resonant inelastic x-ray scattering. This mode, which we term chiral altermagnon, exhibits a distinct momentum dependence of its spin polarization consistent with the altermagnetic g-wave symmetry of MnTe. Our polarization-resolved data corroborate the existence of a discrete class of magnetic excitations, demonstrating how altermagnetic order shapes spin dynamics and paving the way for advances in spintronic and quantum technologies.

▲ 作者：QUENTIN FAURE, DALILA BOUNOUA, VICTOR BALéDENT, ARSEN GUKASOV, V. OVIDIU GARLEA, AFONSO RIBEIRO, ET AL.

▲ 链接：

https://www.science.org/doi/10.1126/science.aec2602

▲ 摘要：

交错磁体是一类具有对称性强制自旋劈裂能带的补偿磁体。学界已在多种材料中发现了支持其存在的直接谱学实验证据。例如，非弹性中子散射（INS）近期用于见证MnTe中与交错磁性相符的磁振子能带劈裂。

研究组给出MnF₂的极化INS测量结果，证明MnF₂属于交错磁体。实验数据揭示，该能带劈裂源于长程偶极耦合。此外，借助畴偏置样品，研究数据揭示了中子散射截面中的非零手性，且两种磁振子模式的符号相反。这一特征明确证实了MnF₂中的交错磁性。

该结果表明，极化INS对磁振子谱的精细结构十分敏感，在表征交错磁体方面具备较大应用前景。

▲ Abstract：

Altermagnets are compensated magnets with symmetry-enforced spin split bands. Direct spectroscopic evidence for their existence has been reported in several materials. For example, inelastic neutron scattering (INS) has recently been used to witness a splitting of magnon bands in MnTe that is compatible with altermagnetism. Here, we present polarized INS results on MnF₂ showing that it is altermagnetic. Our data reveal a splitting coming from the long-range dipolar coupling. Furthermore, using a domain-biased sample, the data reveal a nonzero chirality in the neutron scattering cross section that reverses the sign between the two magnon modes. It is this feature that clearly demonstrates altermagnetism in MnF₂. This finding highlights the potential for polarized INS to characterize altermagnets through its sensitivity to fine structure in magnon spectra.

材料科学Materials Science

▲ 作者：ALI SAFFAR SHAMSHIRGAR, GUILHERME RIBEIRO PORTUGAL, SOHEIL ERSHADRAD, ROMAN IVANOV, MARTIN DAHLQVIST, FLORIAN CHABANAIS, ET AL.

▲ 链接：

https://www.science.org/doi/10.1126/science.aeh5957

▲ 摘要：

MXene是一类发展迅猛的二维过渡金属碳化物与氮化物家族，但其可规模化合成路线仍然有限；以往文献表明该体系存在范围更广、尚未被充分探索的化学空间。

研究组借助机器学习辅助数据库挖掘，发现了新型多层MXene材料。筛选结果揭示了33种已有合成报道、但未被认定为MXene的候选物。在该结果指引下，研究组采用一种快速、可规模化的自蔓延高温合成方法制备出7种多层MXene，该方法无需持续外部加热，数分钟内即可完成反应。

研究组进一步发现了11种此前未见报道的稀土基MXene（M=镨、钕、钐、钆、铽、钬和铥）。实验与建模表明，该系列材料具备半导体特性以及丰富的磁态。这些结果拓展了MXene材料家族，并展示了一种通过可持续方法加速新材料发现的数据驱动策略。

▲ Abstract：

MXenes are a rapidly expanding family of two-dimensional transition metal carbides and nitrides, yet scalable synthesis routes remain limited and historical reports suggest a broader, largely unexplored chemical space. We used machine learning–assisted database mining to uncover hidden multilayer MXenes. Screening reveals 33 previously synthesized but unrecognized MXene candidates. Guided by these findings, we synthesized seven multilayer MXenes using a rapid, scalable self-propagating high-temperature method that requires no sustained external heating and completes within minutes. We further realized 11 previously unexplored rare earth–based MXenes (M = praseodymium, neodymium, samarium, gadolinium, terbium, holmium, and thulium). Experiments and modeling suggest semiconducting behavior and diverse magnetic states across this family. Together, these results expand the MXene family and demonstrate a data-driven strategy for accelerating materials discovery through sustainable methods.

化学Chemistry

▲ 作者：FLORIAN NITZ, STEFAN HRANDL, JONATHAN TZOLD, ALEXANDER KANDRATSENKA, THEOFANIS N. KITSOPOULOS, DANIEL J. AUERBACH, ET AL.

▲ 链接：

https://www.science.org/doi/10.1126/science.aei5255

▲ 摘要：

金属表面吸附质成键依赖局域分子轨道与金属离域电子能带杂化，参与成键的电子波函数可能远超出吸附位点。

研究组通过测定金属表面结构扰动影响分子—金属键强的作用范围，揭示了该离域效应；利用速度分辨动力学，测得三种分子在铂原子台阶上的吸附能。当台阶间距在100埃以上变化时，每个分子的键强变化高达0.2 eV。

该离域效应具有分子特异性，反映了分子特异性轨道与金属特定对称轨道带的杂化，这些轨道带对固体结构修饰有不同的响应。研究组讨论了这些观测结果对铂纳米颗粒吸附的意义。

▲ Abstract：

Adsorbate bonding at metal surfaces requires hybridization of localized molecular orbitals with delocalized electronic bands of the metal; hence, the electronic wave function involved in bonding may extend far beyond the adsorption site. We revealed the consequence of this delocalization by determining the distance over which structural variations of the metal surface influence the molecule-metal bond strength. Velocity-resolved kinetics provided adsorption energies for three molecules bound at atomic steps of platinum (Pt), each exhibiting bond-strength changes of up to 0.2 electron volts as the step-step distance varied over 100 angstroms. We observed molecule-specific behavior reflecting the hybridization of molecule-specific orbitals with symmetry-selected orbital bands of the metal that respond differently to structural modifications of the solid. We discuss implications of these observations for adsorption on Pt nanoparticles.

地球科学Earth Science

▲ 作者：CHRISTOPHE BRABANT, LAURA POLLOCK, JONAS GELDMANN, METTE BENDIXEN, LISE COMTE, HARITH FAROOQ, ET AL.

▲ 链接：

https://www.science.org/doi/10.1126/science.aeb7910▲ 摘要：

人类活动持续破坏生物多样性，淡水系统受冲击尤为严重。目前学界在量化物种脆弱性与威胁方面已取得重大进展，但尚不明确各类威胁在全球哪些地方影响着淡水物种。

研究组从物种视角开展威胁空间评估，绘制了对21490种淡水两栖类、鱼类、哺乳类、蜻蜓目及爬行类中45类威胁的空间影响。结果表明，在高强度开发与人工水文调控区，物种普遍遭受多重威胁。

尽管不同类群和地区的威胁各不相同，但威胁概率升高将推高灭绝风险、加速种群下降。淡水物种的威胁强度高于陆地物种，空间格局也独具特征。该研究结果为精准开展亟需的淡水保护与管理行动提供了一个空间明确的基线。

▲ Abstract：

Human activities are eroding biodiversity, especially in freshwater systems. Despite major advances in quantifying species vulnerability and threats, we still lack a crucial understanding of where threats are affecting freshwater species globally. Here, we produced a species-centered spatial assessment of threats, mapping the impact of 45 threats across 21,490 freshwater species of amphibians, fish, mammals, odonates, and reptiles. We found that species in highly developed and water-managed regions are strongly affected by multiple overlapping threats. Although threats vary across taxa and regions, increasing threat probabilities elevate extinction risk and population declines, with freshwater species experiencing greater threat intensity and distinct spatial patterns than terrestrial species. Our findings establish a spatially explicit baseline for targeting the most urgently needed freshwater conservation and management interventions.

▲ 作者：GUIDO M. GIANNI, XIANG HE, THORSTEN W. BECKER AND CLAUDIO FACCENNA

▲ 链接：

https://www.science.org/doi/10.1126/science.aef5187

▲ 摘要：

大陆裂谷作用反映了构造力与岩石圈强度的平衡，而裂陷机制尚无定论。约600—800万年前加利福尼亚湾斜向裂谷带（GOCOR）的快速裂谷形成是重要实例，其成因可能为岩石圈响应外部运动学条件，或是长期伸展过程加剧，两种模式的动力学机制均尚不明确。

研究组发现，GOCOR快速裂谷事件与西太平洋双向俯冲的起始同步。三维地球动力学模型表明，这种俯冲重组可沿太平洋板块传递5—15兆帕左右的伸展应力，对GOCOR与圣安德烈斯断层南段施加载荷。

俯冲重组或许是触发经历前期改造的岩石圈快速形成GOCOR裂谷的缺失驱动因素，也可能是其他裂谷事件背后被忽略的构造动力。

▲ Abstract：

Continental rifting reflects the balance between tectonic forces and lithospheric strength, yet the mechanisms of breakup remain debated. Rapid rifting of the Gulf of California oblique rift (GOCOR) ~6 million to 8 million years ago is a key example; it may have resulted from the lithosphere responding to external kinematics or acceleration of long-lived extension. The dynamics of either scenario remain incompletely understood. In this study, we highlight that the rapid rifting of the GOCOR coincides with the initiation of Western Pacific double subduction. Using three-dimensional geodynamic models, we show that such subduction reorganization can transmit extensional stresses of ~5 to 15 megapascals across the Pacific plate, loading the GOCOR and the southern San Andreas fault. Subduction reorganization may represent the missing driver for the initiation of rapid GOCOR rifting within a preconditioned lithosphere and may be an overlooked tectonic force behind other rifting events.