Nature,   8 August 2024, Volume 632 Issue 8024

《自然》2024年8月8日，第632卷，8024期

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物理学Physics

Antiferromagnetic phase transition in a 3D fermionic Hubbard model

三维费米子哈伯德模型中的反铁磁相变

▲ 作者：Hou-Ji Shao, Yu-Xuan Wang et al.

▲链接：

https://www.nature.com/articles/s41586-024-07689-2

▲摘要：

费米子哈伯德模型（FHM）描述了由强电子—电子相关性引起的广泛的物理现象，包括非常规超导的推测机制。在此，我们报告了一个由锂-6原子组成的三维费米子哈伯德系统的反铁磁相变的观察，该系统在一个均匀的光学晶格中有大约80万个位点。当相互作用强度、温度和掺杂浓度被微调到接近各自的临界值时，我们观察到自旋结构因子急剧增加。

这些观察结果可以用幂律发散来解释，从海森堡普适性类来看，其临界指数为1.396。在半填充和最佳相互作用强度下，测得的自旋结构因子达到123(8)，表明了反铁磁相的建立。我们的研究结果为探索FHM的低温相图提供了机会。

▲ Abstract：

The fermionic Hubbard model (FHM) describes a wide range of physical phenomena resulting from strong electron–electron correlations, including conjectured mechanisms for unconventional superconductivity. Here we report the observation of the antiferromagnetic phase transition in a three-dimensional fermionic Hubbard system comprising lithium-6 atoms in a uniform optical lattice with approximately 800,000 sites. When the interaction strength, temperature and doping concentration are finely tuned to approach their respective critical values, a sharp increase in the spin structure factor is observed. These observations can be well described by a power-law divergence, with a critical exponent of 1.396 from the Heisenberg universality class. At half-filling and with optimal interaction strength, the measured spin structure factor reaches 123(8), signifying the establishment of an antiferromagnetic phase. Our results provide opportunities for exploring the low-temperature phase diagram of the FHM.

材料科学Materials Science

Water- and heat-activated dynamic passivation for perovskite photovoltaics

钙钛矿光伏电池的水活化和热活化动态钝化

▲ 作者：Wei-Ting Wang, Philippe Holzhey et al.

▲链接：

https://www.nature.com/articles/s41586-024-07705-5

▲摘要：

在此，我们报告了一种使用阻碍脲/硫代氨基甲酸酯键Lewis酸碱材料（HUBLA）的活性钝化策略，其中具有水和热活化特性的动态共价键可以动态修复钙钛矿，以确保设备的性能和稳定性。暴露于湿气或高温下，HUBLA会产生新的试剂，并进一步钝化钙钛矿中的缺陷。

这种钝化策略实现了功率转换效率（PCE）为25.1%的高性能器件。HUBLA设备在85摄氏度的氮气中老化约1500小时后，其初始PCE保持在94%，在85摄氏度和30%相对湿度的空气中老化1000小时后，其初始PCE保持在88%。

▲ Abstract：

Here we report a living passivation strategy using a hindered urea/thiocarbamate bond Lewis acid–base material (HUBLA), where dynamic covalent bonds with water and heat-activated characteristics can dynamically heal the perovskite to ensure device performance and stability. Upon exposure to moisture or heat, HUBLA generates new agents and further passivates defects in the perovskite. This passivation strategy achieved high-performance devices with a power conversion efficiency (PCE) of 25.1 per cent. HUBLA devices retained 94 per cent of their initial PCE for approximately 1,500 hours of ageing at 85 degrees Celsius in nitrogen and maintained 88 per cent of their initial PCE after 1,000 hours of ageing at 85 degrees Celsius and 30 per cent relative humidity in air.

peri-Fused polyaromatic molecular contacts for perovskite solar cells

钙钛矿太阳能电池的聚芳族分子接触

▲ 作者：Ke Zhao, Qingqing Liu et al.

▲链接：

https://www.nature.com/articles/s41586-024-07712-6

▲摘要：

在此，我们报告了一种没有杂原子取代的环绕稠合多环芳烃核心结构，它比传统的杂原子取代核心结构具有更好的载流子传输和选择性。

这种核心结构产生了相对化学惰性和结构刚性的分子接触，可以大大提高钙钛矿太阳能电池在效率和耐用性方面的性能。在不同的加速老化测试中，装置的效率高达26.1%，大大提高了使用寿命。

▲ Abstract：

Here we report a peri-fused polyaromatic core structure without heteroatom substitution that yields superior carrier transport and selectivity over conventional heteroatom-substituted core structures. This core structure produced a relatively chemically inert and structurally rigid molecular contact, which considerably improved the performance of perovskite solar cells in terms of both efficiency and durability. The champion device showed an efficiency up to 26.1% with greatly improved longevity under different accelerated-ageing tests.

化学Chemistry

Hydroamination of alkenes with dinitrogen and titanium polyhydrides

烯烃与二氮和钛多氢化物的氢胺化反应

▲ 作者：Takanori Shima, Qingde Zhuo et al.

▲链接：

https://www.nature.com/articles/s41586-024-07694-5

▲摘要：

在此，我们报告在氢化氚骨架下，简单烯烃与N2的氢胺化反应，这激活了烯烃和N2，导致选择性的C-N键形成，并提供相应的烷基胺进一步氢化和质子化。

计算研究揭示了N2活化和选择性C-N键形成的关键机制细节。这项研究证明了一种通过多核氢化物框架，将N2和简单烃转化为含氮有机化合物的策略。

▲ Abstract：

Here we report the hydroamination of simple alkenes with N2 in a trititanium hydride framework, which activates both alkenes and N2, leading to selective C–N bond formation and providing the corresponding alkyl amines on further hydrogenation and protonation. Computational studies reveal key mechanistic details of N2 activation and selective C–N bond formation. This work demonstrates a strategy for the transformation of N2 and simple hydrocarbons into nitrogen-containing organic compounds mediated by a multinuclear hydride framework.

地球科学 Earth Science

Highest ocean heat in four centuries places Great Barrier Reef in danger

四个世纪以来最高的海洋温度使大堡礁处于危险之中

▲ 作者：Benjamin J. Henley, Helen V. McGregor et al.

▲链接：

https://www.nature.com/articles/s41586-024-07672-x

▲摘要：

在此，我们表明在2024年、2017年和2020年（按平均海温异常降序排列）1月至3月的珊瑚海极端高温是400年来最温暖的，超过了我们重建的1900年前最大值的95个百分位不确定性极限。

2016年、2004年和2022年的高温排名第二，超过了第90个百分位数的限制。气候模式分析证实，人类对气候系统的影响是近几十年来快速变暖的原因。这一归因，加上最近的海洋极端温度、1900年后的变暖趋势和观测到的大规模珊瑚白化，表明人为气候变化对大堡礁生态系统的生存威胁现在已经形成。

如果不采取紧急干预措施，标志性的大堡礁将面临气温升高的风险，这将导致近乎每年的珊瑚白化，对生物多样性和生态系统产生负面影响。如果按照目前的轨迹继续下去，将进一步威胁到地球上最伟大的自然奇观之一的生态功能和突出的普遍价值。

▲ Abstract：

Here we show that the January–March Coral Sea heat extremes in 2024, 2017 and 2020 (in order of descending mean SST anomalies) were the warmest in 400 years, exceeding the 95th-percentile uncertainty limit of our reconstructed pre-1900 maximum. The 2016, 2004 and 2022 events were the next warmest, exceeding the 90th-percentile limit. Climate model analysis confirms that human influence on the climate system is responsible for the rapid warming in recent decades. This attribution, together with the recent ocean temperature extremes, post-1900 warming trend and observed mass coral bleaching, shows that the existential threat to the GBR ecosystem from anthropogenic climate change is now realized. Without urgent intervention, the iconic GBR is at risk of experiencing temperatures conducive to near-annual coral bleaching, with negative consequences for biodiversity and ecosystems services. A continuation on the current trajectory would further threaten the ecological function and outstanding universal value of one of Earth’s greatest natural wonders.

Cenozoic history of the tropical marine biodiversity hotspot

热带海洋生物多样性热点地区的新生代历史

▲ 作者：Skye Yunshu Tian, Moriaki Yasuhara et al.

▲链接：

https://www.nature.com/articles/s41586-024-07617-4

▲摘要：

地球上海洋生物多样性最高的地区被称为珊瑚三角或印澳群岛（IAA）。在此，我们利用一个全面的化石数据集，通过推断物种灭绝动态，对IAA的新生代的多样性历史进行了高分辨率的重建。

我们发现，自2500万年前以来，IAA呈现出单向多样化的趋势，大致呈对数增长，直到大约260万年前开始出现多样性稳定期。

1390万年前以后，生物多样性的增长主要受生物多样性依赖和生境大小的控制，热应力的缓解也促进了生物多样性的增长。不同的净多样化高峰记录在大约2500万年前、2000万年前、1600万年前、1200万年前和500万年前，这可能与主要的构造事件以及气候变化有关。

关键的生物地理过程对IAA的多样性产生了深远的影响，表现在Tethyan后裔的长期衰落和世界性和IAA分类群的长期繁荣。最后，没有大灭绝和新生代冷却似乎是使IAA成为地球上海洋生物多样性最丰富的热点的关键。

▲ Abstract：

The region with the highest marine biodiversity on our planet is known as the Coral Triangle or Indo-Australian Archipelago (IAA). Here we present a high-resolution reconstruction of the Cenozoic diversity history of the IAA by inferring speciation–extinction dynamics using a comprehensive fossil dataset. We found that the IAA has exhibited a unidirectional diversification trend since about 25 million years ago, following a roughly logistic increase until a diversity plateau beginning about 2.6 million years ago. The growth of diversity was primarily controlled by diversity dependency and habitat size, and also facilitated by the alleviation of thermal stress after 13.9 million years ago. Distinct net diversification peaks were recorded at about 25, 20, 16, 12 and 5 million years ago, which were probably related to major tectonic events in addition to climate transitions. Key biogeographic processes had far-reaching effects on the IAA diversity as shown by the long-term waning of the Tethyan descendants versus the waxing of cosmopolitan and IAA taxa. Finally, it seems that the absence of major extinctions and the Cenozoic cooling have been essential in making the IAA the richest marine biodiversity hotspot on Earth.