编译 | 李言

Nature, 11 August 2022, Volume 608 Issue 7922

《自然》 2022年8月11日，第608卷，7922期

材料科学Material Science

Quantum cascade of correlated phases in trigonally warped bilayer graphene

三角弯曲双层石墨烯中相关相的量子级联

▲ 作者：Anna M. Seiler, Fabian R. Geisenhof, Felix Winterer et al.

▲ 链接：

https://www.nature.com/articles/s41586-022-04937-1

▲ 摘要：

在此，我们报告在伯纳尔双层石墨烯中电场控制的Lifshitz转变和范霍夫奇点附近观察到的一系列相关相。我们为观察到以半金属和四分之一金属形式的斯通纳铁磁体提供了证据。

此外，我们确定了在零磁场下拓扑非平凡维格纳-霍尔晶体及其向平凡维格纳晶体转变的特征，以及两种行为与标准费米液体的行为相偏离的相关金属。我们在这个可重复的、可调的、简单的系统中的结果为研究强相关电子研究打开了新的视野。

▲ Abstract：

Here we report the observation of a cascade of correlated phases in the vicinity of electric-field-controlled Lifshitz transitions and van Hove singularities in Bernal bilayer graphene. We provide evidence for the observation of Stoner ferromagnets in the form of half and quarter metals. Furthermore, we identify signatures consistent with a topologically non-trivial Wigner–Hall crystal at zero magnetic field and its transition to a trivial Wigner crystal, as well as two correlated metals whose behaviour deviates from that of standard Fermi liquids. Our results in this reproducible, tunable, simple system open up new horizons for studying strongly correlated electrons.

A mechanically strong and ductile soft magnet with extremely low coercivity

一种高强高塑、极低矫顽力的软磁体

▲ 作者：Liuliu Han, Fernando Maccari, Isnaldi R. Souza Filho et al.

▲ 链接：

https://www.nature.com/articles/s41586-022-04935-3

▲ 摘要：

交通、家庭和制造业的电气化，由于滞后损失，导致能源消耗增加。因此，降低矫顽力是至关重要的，它可以衡量这些损失。然而，仅仅实现这一目标是不够的：电机中的微型微结构元件必须承受严重的机械负载；也就是说，合金需要高强度和延展性。

在此，我们介绍一种克服此类困境的方法。我们设计了一种Fe-Co-Ni-Ta-Al多元合金（MCA），它具有铁磁基体和顺磁性相干纳米颗粒（尺寸约为 91nm，体积分数约为 55%）。它们阻碍位错运动，增加强度和延展性。它们的小尺寸、低相干应力和小静磁能在磁畴壁宽度以下产生相互作用体积，导致畴壁钉扎最小化，从而保持软磁性。

这种合金在54%的拉伸伸长率下抗拉强度为1336 MPa，矫顽力为78 Am−1（小于1 Oe），饱和磁化强度为100 A m2 kg−1，电阻率为103 μΩ cm。

▲ Abstract：

The electrification of transport, households and manufacturing leads to an increase in energy consumption owing to hysteresis losses. Therefore, minimizing coercivity, which scales these losses, is crucial. Yet meeting this target alone is not enough: SMMs in electrical engines must withstand severe mechanical loads; that is, the alloys need high strength and ductility. Here we introduce an approach to overcome this dilemma. We have designed a Fe–Co–Ni–Ta–Al multicomponent alloy (MCA) with ferromagnetic matrix and paramagnetic coherent nanoparticles (about 91 nm in size and around 55% volume fraction). They impede dislocation motion, enhancing strength and ductility. Their small size, low coherency stress and small magnetostatic energy create an interaction volume below the magnetic domain wall width, leading to minimal domain wall pinning, thus maintaining the soft magnetic properties. The alloy has a tensile strength of 1,336 MPa at 54% tensile elongation, extremely low coercivity of 78 Am−1 (less than 1 Oe), moderate saturation magnetization of 100 A m2 kg−1 and high electrical resistivity of 103 μΩ cm.

物理学Physics

Self-emergence of robust solitons in a microcavity

微腔中鲁棒孤子的自出现

▲ 作者：Maxwell Rowley, Pierre-Henry Hanzard, Antonio Cutrona et al.

▲ 链接：

https://www.nature.com/articles/s41586-022-04957-x

▲ 摘要：

在此，我们展示了自由运行的微谐振滤波器光纤激光器的慢非线性可以将时间腔孤子转化为系统的主要吸引子。这一现象导致了微腔孤子可靠的自启动振荡，对扰动具有天然的鲁棒性，即使在完全中断后也能自动恢复。

这些情况可在球形系统参数空间的的大区域中重复且可控地出现，在这个区域中，可以实现特定状态的长期高度稳定。

▲ Abstract：

Here we show that the slow non-linearities of a free-running microresonator-filtered fibre laser can transform temporal cavity solitons into the system’s dominant attractor. This phenomenon leads to reliable self-starting oscillation of microcavity solitons that are naturally robust to perturbations, recovering spontaneously even after complete disruption. These emerge repeatably and controllably into a large region of the global system parameter space in which specific states, highly stable over long timeframes, can be achieved.

地球科学Earth science

Giant impacts and the origin and evolution of continents

大碰撞及大陆的起源和演化

▲ 作者：Tim E. Johnson, Christopher L. Kirkland, Yongjun Lu et al.

▲ 链接：

https://www.nature.com/articles/s41586-022-04956-y

▲ 摘要：

地球是已知的唯一有大陆的行星，尽管大陆形成和演化的方式尚不清楚。在此，通过对岩浆锆石的氧同位素分析，我们发现西澳大利亚皮尔巴拉克拉顿是地球上保存最完好的太古宙（40 - 25亿年前）大陆遗迹，它的形成经历了三个阶段。第一阶段锆石（3.6 ~ 3.4 Ga）形成两个团簇，其中1 / 3记录为下地幔δ18O，表明岩浆来自于热液蚀变的玄武岩地壳（如今天的冰岛）。

浅层融化与代表地球最初10亿年历史的大碰撞是一致的。大碰撞为地壳破裂提供了动力，并通过与全球广泛的海洋的相互作用建立了长期的热液蚀变。大约发生在3.6 Ga的一次巨大撞击，与最古老的低δ18O锆石同时代，可能会触发大规模的地幔融化，产生厚的镁铁质-超镁铁质核。

另一个低δ18O锆石簇约为3.4 Ga，与球粒层同生，为地球上的巨大撞击提供了最古老的物质证据。第2阶段（3.4 ~ 3.0 Ga）锆石的δ18O多为类似地幔δ18O，主要来源于大陆核基底附近的母岩浆。第三阶段（<3.0 Ga）锆石δ18O具有上地幔特征，反映了表壳岩石的高效循环。最古老的长英质岩石形成于3.9-3.5 Ga，接近所谓的晚期重轰击末期，并非巧合。

▲ Abstract：

Earth is the only planet known to have continents, although how they formed and evolved is unclear. Here using the oxygen isotope compositions of dated magmatic zircon, we show that the Pilbara Craton in Western Australia, Earth’s best-preserved Archaean (4.0–2.5 billion years ago (Ga)) continental remnant, was built in three stages. Stage 1 zircons (3.6–3.4 Ga) form two age clusters with one-third recording submantle δ18O, indicating crystallization from evolved magmas derived from hydrothermally altered basaltic crust like that in modern-day Iceland. Shallow melting is consistent with giant impacts that typified the first billion years of Earth history. Giant impacts provide a mechanism for fracturing the crust and establishing prolonged hydrothermal alteration by interaction with the globally extensive ocean. A giant impact at around 3.6 Ga, coeval with the oldest low-δ18O zircon, would have triggered massive mantle melting to produce a thick mafic–ultramafic nucleus. A second low-δ18O zircon cluster at around 3.4 Ga is contemporaneous with spherule beds that provide the oldest material evidence for giant impacts on Earth. Stage 2 (3.4–3.0 Ga) zircons mostly have mantle-like δ18O and crystallized from parental magmas formed near the base of the evolving continental nucleus. Stage 3 (<3.0 Ga) zircons have above-mantle δ18O, indicating efficient recycling of supracrustal rocks. That the oldest felsic rocks formed at 3.9–3.5 Ga, towards the end of the so-called late heavy bombardment, is not a coincidence.

生物学Biology

Dairying, diseases and the evolution of lactase persistence in Europe

欧洲的乳业、疾病和乳糖酶持久性的演变

▲ 作者：Richard P. Evershed, George Davey Smith, Mélanie Roffet-Salque et al.

▲ 链接：

https://www.nature.com/articles/s41586-022-05010-7

▲ 摘要：

在欧洲和许多非洲、中东和南亚人口中，乳糖耐受性（LP）是在过去1万年中进化出来的最强烈的单基因性状。在此，我们提供了欧洲在过去9000年里在550多个考古遗址的约7000个陶器脂肪残留物中提取牛奶的详细分布。从新石器时代，欧洲开始广泛饮用牛奶，但在空间和时间上的强度不同。

值得注意的是，与新石器时代，随着史前牛奶饮用水平的不同而变化的乳糖耐受性选择并不更能解释乳糖耐受性等位基因频率轨迹。在英国生物库50万名当代欧洲人的队列研究中，乳糖耐受性基因型与牛奶摄入量的相关性较弱，与改善体质或健康指标的相关性不一致。这表明，乳糖耐受性的频率快速增加应考虑其他原因，使其有益的影响。

我们认为，乳糖酶不持久的个体在牛奶有供应时饮用牛奶，但在饥荒和/或病原体暴露增加的条件下不饮用，推动了史前欧洲人的乳糖耐受性选择。模型似然值的比较表明，种群波动、聚居密度和野生动物开发利用作为这些驱动因素的替代物，比牛奶饮用程度更能解释乳糖耐受性的改变。这些发现为史前牛奶饮用和乳糖耐受性进化提供了新的视角。

▲ Abstract：

In European and many African, Middle Eastern and southern Asian populations, lactase persistence (LP) is the most strongly selected monogenic trait to have evolved over the past 10,000 years. Here we provide detailed distributions of milk exploitation across Europe over the past 9,000 years using around 7,000 pottery fat residues from more than 550 archaeological sites. European milk use was widespread from the Neolithic period onwards but varied spatially and temporally in intensity. Notably, LP selection varying with levels of prehistoric milk exploitation is no better at explaining LP allele frequency trajectories than uniform selection since the Neolithic period. In the UK Biobank cohort of 500,000 contemporary Europeans, LP genotype was only weakly associated with milk consumption and did not show consistent associations with improved fitness or health indicators. This suggests that other reasons for the beneficial effects of LP should be considered for its rapid frequency increase. We propose that lactase non-persistent individuals consumed milk when it became available but, under conditions of famine and/or increased pathogen exposure, this was disadvantageous, driving LP selection in prehistoric Europe. Comparison of model likelihoods indicates that population fluctuations, settlement density and wild animal exploitation—proxies for these drivers—provide better explanations of LP selection than the extent of milk exploitation. These findings offer new perspectives on prehistoric milk exploitation and LP evolution.

古生物学Paleontology

The developing bird pelvis passes through ancestral dinosaurian conditions

鸟类骨盆发育中的祖先恐龙特征

▲ 作者：Christopher T. Griffin, João F. Botelho, Michael Hanson et al.

▲ 链接：

https://www.nature.com/articles/s41586-022-04982-w

▲ 摘要：

我们使用胚胎学成像技术在三个维度上检查鸟类盆腔组织的形态发生，与化石记录进行直接比较。许多恐龙祖先的特征（例如，前向耻骨、短髂骨和耻骨）在鸟类的早期形态发生中短暂存在，并通过反映特征获得的系统发育序列的产前发育序列过渡后达到典型的“活鸟”形态。

我们定量地证明了鸟类骨盆个体发生与非鸟类恐龙到鸟类的转变相似，并为骨盆内表型协方差提供了证据。鸟类胚胎中存在的祖先状态可能源于这种保守的协变关系。

总之，我们的数据提供了证据，证明鸟类骨盆的早期发育是通过末端附加的机制进化的，即新的非形形状态被添加到发育序列的末端，导致该序列中更早的祖先特征状态的表达。

▲ Abstract：

We used embryological imaging techniques to examine the morphogenesis of avian pelvic tissues in three dimensions, allowing direct comparison with the fossil record. Many ancestral dinosaurian features (for example, a forward-facing pubis, short ilium and pubic ‘boot’) are transiently present in the early morphogenesis of birds and arrive at their typical ‘avian’ form after transitioning through a prenatal developmental sequence that mirrors the phylogenetic sequence of character acquisition. We demonstrate quantitatively that avian pelvic ontogeny parallels the non-avian dinosaur-to-bird transition and provide evidence for phenotypic covariance within the pelvis that is conserved across Archosauria. The presence of ancestral states in avian embryos may stem from this conserved covariant relationship. In sum, our data provide evidence that the avian pelvis, whose early development has been little studied, evolved through terminal addition—a mechanism whereby new apomorphic states are added to the end of a developmental sequence, resulting in expression8,11 of ancestral character states earlier in that sequence.