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Nature, 8 August 2024, Volume 632 Issue 8024 《天然》2024年8月8日,第632卷,8024期 物理学Physics Antiferromagnetic phase transition in a 3D fermionic Hubbard model 三维费米子哈伯德模子中的反铁磁相变 ▲ 作者:Hou-Ji Shao, Yu-Xuan Wang et al. ▲链接: https://www.nature.com/articles/s41586-024-07689-2 ▲择要: 费米子哈伯德模子(FHM)描写了由强电子—电子相干性惹起的广泛的物理征象,包孕很是规超导的猜度机制。于此,咱们陈诉了一个由锂-6原子构成的三维费米子哈伯德体系的反铁磁相变的不雅察,该体系于一个匀称的光学晶格中有约莫80万个位点。当彼此作用强度、温度以及掺杂浓度被微调到靠近各自的临界值时,咱们不雅察到自旋布局因子急剧增长。 这些不雅察成果可以用幂律发散来注释,从海森堡普适性类来看,其临界指数为1.396。于半填充以及最好彼此作用强度下,测患上的自旋布局因子到达123(8),注解了反铁磁相的成立。咱们的研究成果为摸索FHM的低温相图提供了时机。 ▲ 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. 质料科学Materials Science Water- and heat-activated dynamic passivation for perovskite photovoltaics 钙钛矿光伏电池的水活化以及热活化动态钝化 ▲ 作者:Wei-Ting Wang, Philippe Holzhey et al. ▲链接: https://www.nature.com/articles/s41586-024-07705-5 ▲择要: 于此,咱们陈诉了一种使用拦阻脲/硫代氨基甲酸酯键Lewis酸碱质料(HUBLA)的活性钝化计谋,此中具备水以及热活化特征的动态共价键可以动态修复钙钛矿,以确保装备的机能以及不变性。袒露在湿气或者高温下,HUBLA会孕育发生新的试剂,并进一步钝化钙钛矿中的缺陷。 这类钝化计谋实现了功率转换效率(PCE)为25.1%的高机能器件。HUBLA装备于85摄氏度的氮气中老化约1500小时后,其初始PCE连结于94%,于85摄氏度以及30%相对于湿度的空气中老化1000小时后,其初始PCE连结于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份子接触 ▲ 作者:Ke Zhao, Qingqing Liu et al. ▲链接: https://www.nature.com/articles/s41586-024-07712-6 ▲择要: 于此,咱们陈诉了一种没有杂原子代替的环抱稠合多环芳烃焦点布局,它比传统的杂原子代替焦点布局具备更好的载流子传输以及选择性。 这类焦点布局孕育发生了相对于化学惰性以及布局刚性的份子接触,可以年夜年夜提高钙钛矿太阳能电池于效率以及耐用性方面的机能。于差别的加快老化测试中,装配的效率高达26.1%,年夜年夜提高了使用寿命。 ▲ 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 烯烃与二氮以及钛多氢化物的氢胺化反映 ▲ 作者:Takanori Shima, Qingde Zhuo et al. ▲链接: https://www.nature.com/articles/s41586-024-07694-5 ▲择要: 于此,咱们陈诉于氢化氚骨架下,简朴烯烃与N2的氢胺化反映,这激活了烯烃以及N2,致使选择性的C-N键造成,并提供响应的烷基胺进一步氢化以及质子化。 计较研究展现了N2活化以及选择性C-N键造成的要害机制细节。这项研究证实了一种经由过程多核氢化物框架,将N2以及简朴烃转化为含氮无机化合物的计谋。 ▲ 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年夜堡礁处在伤害之中 ▲ 作者:Benjamin J. Henley, Helen V. McGregor et al. ▲链接: https://www.nature.com/articles/s41586-024-07672-x ▲择要: 于此,咱们注解于2024年、2017年以及2020年(按平均海温异样降序摆列)1月至3月的珊瑚海极度高温是400年来最温馨的,跨越了咱们重修的1900年前最年夜值的95个百分位不确定性极限。 2016年、2004年以及2022年的高温排名第二,跨越了第90个百分位数的限定。天气模式阐发证明,人类对于天气体系的影响是近几十年来倏地变暖的缘故原由。这一归因,加之近来的海洋极度温度、1900年后的变暖趋向以及不雅测到的年夜范围珊瑚白化,注解报酬天气变迁对于年夜堡礁生态体系的保存威逼此刻已经经造成。 假如不采纳紧迫干涉干与办法,标记性的年夜堡礁将面对气温升高的危害,这将致使近乎每一年的珊瑚白化,对于生物多样性以及生态体系孕育发生负面影响。假如根据今朝的轨迹继承下去,将进一步威逼到地球上最巨大的天然异景之一的生态功效以及凸起的遍及价值。 ▲ 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门地域的新生代汗青 ▲ 作者:Skye Yunshu Tian, Moriaki Yasuhara et al. ▲链接: https://www.nature.com/articles/s41586-024-07617-4 ▲择要: 地球上海洋生物多样性最高的地域被称为珊瑚三角或者印澳群岛(IAA)。于此,咱们哄骗一个周全的化石数据集,经由过程揣度物种灭尽动态,对于IAA的新生代的多样性汗青举行了高分辩率的重修。 咱们发明,自2500万年前以来,IAA出现出单向多样化的趋向,大抵呈对于数增加,直到约莫260万年前最先呈现多样性不变期。 1390万年前之后,生物多样性的增加重要受生物多样性依靠以及生境巨细的节制,热应力的减缓也促成了生物多样性的增加。差别的净多样化岑岭记载于约莫2500万年前、2000万年前、1600万年前、1200万年前以及500万年前,这可能与重要的组织事务和天气变迁有关。 要害的生物地舆历程对于IAA的多样性孕育发生了深远的影响,体现于Tethyan后裔的持久式微以及世界性以及IAA分类群的持久繁荣。末了,没有年夜灭尽以及新生代冷却好像是使IAA成为地球上海洋生物多样性最富厚的热门的要害。 ▲ Abstract: The region with the highest marine biodiversity on our planet is known as the Coral Triangle or Indo-澳大利亚n 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.