编译 | 李言

Nature, 1 February 2024, Volume 626 Issue 7997

《自然》, 2024年2月1日，第626卷，7997期

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物理学Physics

Observation of interband Berry phase in laser-driven crystals

激光驱动晶体中的带间贝里相位的观察

▲ 作者：Ayelet J. Uzan-Narovlansky, Lior Faeyrman et al.

▲ 链接：

https://www.nature.com/articles/s41586-023-06828-5

▲ 摘要：

在此，我们演示了驱动晶体中贝里相位的一种新表现，其中电子波函数在不同波段之间的离散演化过程中积累几何相位，同时保持过程的相干性。

我们通过实验揭示了这一相位，通过使用强激光场来设计内部干涉仪，在不到一个驱动场的周期内诱导，将相位映射到高次谐波的发射上。

我们的工作为几何相位的研究提供了机会，可以便于在光驱动拓扑现象和阿秒固体物理中进行各种观测。

▲ Abstract：

Here we introduce and demonstrate a conceptually new manifestation of the Berry phase in light-driven crystals, in which the electronic wavefunction accumulates a geometric phase during a discrete evolution between different bands, while preserving the coherence of the process. We experimentally reveal this phase by using a strong laser field to engineer an internal interferometer, induced during less than one cycle of the driving field, which maps the phase onto the emission of higher-order harmonics. Our work provides an opportunity for the study of geometric phases, leading to a variety of observations in light-driven topological phenomena and attosecond solid-state physics.

材料科学Materials Science

High-quality semiconductor fibres via mechanical design

通过机械设计制备高质量半导体纤维

▲ 作者：Zhixun Wang, Zhe Wang et al.

▲ 链接：

https://www.nature.com/articles/s41586-023-06946-0

▲ 摘要：

在此，我们通过研究纤维形成的三个阶段（粘性流动、芯结晶和随后的冷却）的应力发展和毛细不稳定性，报告了一种可以实现超长、无断裂和无扰动无机半导体纤维的机械设计。

然后，可以将暴露的半导体线集成到单一的柔性光纤中，并与金属电极具有良好的接口，从而实现光电光纤和大规模光电织物。这项研究提供了极端力学和流体动力学的见解，这些几何形状在传统平台中是无法实现的，从而解决了对柔性和可穿戴光电子器件日益增长的需求。

▲ Abstract：

Here we report a mechanical design to achieve ultralong, fracture-free and perturbation-free semiconductor fibres, guided by a study on stress development and capillary instability at three stages of the fibre formation: the viscous flow, the core crystallization and the subsequent cooling stage. Then, the exposed semiconductor wires can be integrated into a single flexible fibre with well-defined interfaces with metal electrodes, thereby achieving optoelectronic fibres and large-scale optoelectronic fabrics. This work provides fundamental insights into extreme mechanics and fluid dynamics with geometries that are inaccessible in traditional platforms, essentially addressing the increasing demand for flexible and wearable optoelectronics.

化学Chemistry

Structural transition and migration of incoherent twin boundary in diamond

金刚石中非共格孪晶界的结构转变与迁移

▲ 作者：Ke Tong, Xiang Zhang, Zihe Li et al.

▲ 链接：

https://www.nature.com/articles/s41586-023-06908-6

▲ 摘要：

在此，我们报告了在室温下金刚石中六种非共格孪晶界（ITB）特征和结构转变的原子观察，显示了不同于金属系统的位错介导机制。主导ITBs不对称且流动性较差，对纳米孪晶金刚石的持续硬化起重要作用。

我们的研究结果揭示了金刚石和共价材料中的晶界行为，指出了开发高性能纳米孪晶材料的新策略。

▲ Abstract：

Here we report atomic observations of six ITB configurations and structural transitions in diamond at room temperature, showing a dislocation-mediated mechanism different from metallic systems. The dominant ITBs are asymmetric and less mobile, contributing strongly to continuous hardening in nanotwinned diamond. The potential driving forces of ITB activities are discussed. Our findings shed new light on GB behaviour in diamond and covalent materials, pointing to a new strategy for development of high-performance, nanotwinned materials.

Durable CO₂ conversion in the proton-exchange membrane system

质子交换膜系统中持久的二氧化碳转化

▲ 作者：Wensheng Fang, Wei Guo, Ruihu Lu et al.

▲ 链接：

https://www.nature.com/articles/s41586-023-06917-5

▲ 摘要：

在此，我们开发了一种质子交换膜系统，该系统在源自废铅酸电池的催化剂下将二氧化碳还原为甲酸，其中晶格碳活化机制起作用。当二氧化碳还原与氢氧化耦合时，甲酸法拉第效率超过93%。

该系统与启动/关闭过程兼容，在电流密度为600 mA cm^-2和电池电压为2.2 V的情况下，二氧化碳的单通转换效率接近91%，连续工作时间超过5200小时。我们期望通过使用强大而高效的催化剂、稳定的三相界面和耐用的膜，这种卓越的性能将有助于推动碳中和技术的发展。

▲ Abstract：

Herein we develop a proton-exchange membrane system that reduces CO₂ to formic acid at a catalyst that is derived from waste lead–acid batteries and in which a lattice carbon activation mechanism contributes. When coupling CO₂ reduction with hydrogen oxidation, formic acid is produced with over 93% Faradaic efficiency. The system is compatible with start-up/shut-down processes, achieves nearly 91% single-pass conversion efficiency for CO₂ at a current density of 600 mA cm^-2 and cell voltage of 2.2 V and is shown to operate continuously for more than 5,200 h. We expect that this exceptional performance, enabled by the use of a robust and efficient catalyst, stable three-phase interface and durable membrane, will help advance the development of carbon-neutral technologies.

Stereodivergent 1,3-difunctionalization of alkenes by charge relocation

通过电荷重定位研究烯烃立体发散1,3-双官能化

▲ 作者：Bogdan R. Brutiu, Giulia Iannelli et al.

▲ 链接：

https://www.nature.com/articles/s41586-023-06938-0

▲ 摘要：

在此，我们介绍一种基于名为“电荷重定位”概念的1,3-烯烃直接双官能团化方法，该方法可以使未活化的烯烃以立体发散的方式获得正构或反构的1,3-双官能团化产物，而不需要定向基团或稳定特征。该方法的有效性在肺毒素4-ipomeanol及其衍生物的合成中得到了证明。

▲ Abstract：

Here we introduce a method for the direct 1,3-difunctionalization of alkenes, based on a concept termed ‘charge relocation’, which enables stereodivergent access to 1,3-difunctionalized products of either syn- or anti-configuration from unactivated alkenes, without the need for directing groups or stabilizing features. The usefulness of the approach is demonstrated in the synthesis of the pulmonary toxin 4-ipomeanol and its derivatives.

生态学Ecology

Top-predator recovery abates geomorphic decline of a coastal ecosystem

顶级捕食者复苏减缓了沿海生态系统的地貌退化

▲ 作者：Brent B. Hughes, Kathryn M. Beheshti et al.

▲ 链接：

https://www.nature.com/articles/s41586-023-06959-9

▲ 摘要：

在此，我们将观测和实验数据结合起来，揭示了海獭在美国河口的重新定居产生了一个营养级联，促进了沿海湿地植物的生物量，抑制了沼泽边缘的侵蚀，否则这一过程会导致栖息地和生态系统服务的严重丧失。

几十年来对Elkhorn Slough河口的监测表明，该系统中存在自上而下的控制，因为尽管系统中的物理压力（即营养负荷、海平面上升和潮汐冲刷）持续增加，但随着海獭数量的增加，盐沼边缘的侵蚀总体上有所减缓。在5条沼泽小溪中进行的捕食者排除实验表明，海獭抑制了穴居蟹的数量，这是一种自上而下的效应，它增加了沼泽边缘的强度，减少了沼泽的侵蚀。

多条溪流的调查比较了海獭定居前后的沼泽溪，证实了关键海獭、穴居蟹和沼泽溪之间存在相互作用，证明了捕食者控制生态系统边缘过程的空间普遍性：在海獭重新定居水平较高的小溪中，穴居蟹的密度和边缘侵蚀明显下降。这些结果表明，营养退化可能是导致沿海湿地丧失的一个重要、但未被充分认识的因素，这表明顶级捕食者的复苏有助于重建地貌稳定性。

▲ Abstract：

Here we combine observational and experimental data to reveal that recolonization of sea otters in a US estuary generates a trophic cascade that facilitates coastal wetland plant biomass and suppresses the erosion of marsh edges—a process that otherwise leads to the severe loss of habitats and ecosystem services. Monitoring of the Elkhorn Slough estuary over several decades suggested top-down control in the system, because the erosion of salt marsh edges has generally slowed with increasing sea otter abundance, despite the consistently increasing physical stress in the system (that is, nutrient loading, sea-level rise and tidal scour). Predator-exclusion experiments in five marsh creeks revealed that sea otters suppress the abundance of burrowing crabs, a top-down effect that cascades to both increase marsh edge strength and reduce marsh erosion. Multi-creek surveys comparing marsh creeks pre- and post-sea otter colonization confirmed the presence of an interaction between the keystone sea otter, burrowing crabs and marsh creeks, demonstrating the spatial generality of predator control of ecosystem edge processes: densities of burrowing crabs and edge erosion have declined markedly in creeks that have high levels of sea otter recolonization. These results show that trophic downgrading could be a strong but underappreciated contributor to the loss of coastal wetlands, and suggest that restoring top predators can help to re-establish geomorphic stability.