编译 | 李言

Nature, 25 November 2021, Volume 599 Issue 7886

《自然》2021年11月25日上海晶永广告seo招聘，第599卷，7886期

材料科学Material Science

Ultrahard bulk amorphous carbon from collapsed fullerene

来自塌陷富勒烯的极硬非晶碳

▲ 作者上海晶永广告seo招聘：Yuchen Shang, Zhaodong Liu, Jiajun Dong, Mingguang Yao, Zhenxing Yang, Quanjun Li et al.

▲ 链接上海晶永广告seo招聘：

https://www.nature.com/articles/s41586-021-03882-9

▲ 摘要

在此，我们成功地合成了毫米级近全sp3的非晶碳块体，其体积是之前研究的103–104倍。合成的材料由许多随机取向的类金刚石簇组成，具有已知非晶材料中最高的硬度(101.9±2.3 GPa)、弹性模量(1182±40 GPa)和热导率(26.0±1.3 W m?1?K?1)。

它的光学带隙从1.85 eV可调到2.79 eV。这些发现有助于我们了解高级非晶材料和通过高压和高温技术合成大块非晶材料，并可能发展出非晶固体的新应用方式。

▲ Abstract

Here, we successfully synthesized millimetre-sized samples—with volumes 103–104 times as large as produced in earlier studies—of transparent, nearly pure sp3 amorphous carbon by heating fullerenes at pressures close to the cage collapse boundary. The material synthesized consists of many randomly oriented clusters with diamond-like short-/medium-range order and possesses the highest hardness (101.9?±?2.3?GPa), elastic modulus (1,182?±?40?GPa) and thermal conductivity (26.0?±?1.3?W?m?1?K?1) observed in any known amorphous material. It also exhibits optical bandgaps tunable from 1.85?eV to 2.79?eV. These discoveries contribute to our knowledge about advanced amorphous materials and the synthesis of bulk amorphous materials by high-pressure and high-temperature techniques and may enable new applications for amorphous solids.

Synthesis of paracrystalline diamond

次晶态金刚石的合成

▲ 作者：Hu Tang, Xiaohong Yuan, Yong Cheng, Hongzhan Fei, Fuyang Liu et al.

▲ 链接：

https://www.nature.com/articles/s41586-021-04122-w

▲ 摘要

在此，我们报告一种有别于晶体或非晶金刚石的次晶态金刚石。这项研究中报告的次晶态金刚石由具有中程尺度范围几个原子层的亚纳米尺寸次晶构成，是在高压高温条件（例如30GPa、1600K）对立方C60前驱体进行处理合成的。

通过x射线衍射、高分辨率透射显微镜和先进的分子动力学模拟，确定了该次晶态金刚石的结构特征。次晶态金刚石的形成是由于压缩C60中密集分布的成核位点和非晶金刚石中明显的第二近邻短程有序（强sp3键合）的结果。

▲ Abstract

Here we report a paracrystalline state of diamond that is distinct from either crystalline or amorphous diamond. The paracrystalline diamond reported in this work, consisting of sub-nanometre-sized paracrystallites that possess a well-defined crystalline medium-range order up to a few atomic shells, was synthesized in high-pressure high-temperature conditions (for example, 30?GPa and 1,600?K) employing face-centred cubic C60 as a precursor. The structural characteristics of the paracrystalline diamond were identified through a combination of X-ray diffraction, high-resolution transmission microscopy and advanced molecular dynamics simulation. The formation of paracrystalline diamond is a result of densely distributed nucleation sites developed in compressed C60 as well as pronounced second-nearest-neighbour short-range order in amorphous diamond due to strong sp3 bonding.

Colossal angular magnetoresistance in ferrimagnetic nodal-line semiconductors

亚铁磁节点线半导体中的巨大角磁电阻

▲ 作者：Junho Seo, Chandan De, Hyunsoo Ha, Ji Eun Lee, Sungyu Park, Joonbum Park et al.

▲ 链接：

https://www.nature.com/articles/s41586-021-04028-7

▲ 摘要

在此，我们提出磁半导体中自旋极化带的拓扑节点线简并引起极大的角响应磁运输。以层状铁磁体Mn3Si2Te6及其衍生化合物为模型系统，研究了手性分子轨道态驱动的拓扑能带简并度随自旋取向而提高，从而导致同一铁磁体相中的金属-绝缘体转变。

由此产生的角磁电阻随旋转磁化强度的变化超过每弧度百分之一万亿，我们称之为巨大的角磁电阻。我们的研究结果表明，磁性节点线半导体是实现极其敏感的自旋和轨道依赖功能的一个有前途的平台。

▲ Abstract

Here we propose that the topological nodal-line degeneracy of spin-polarized bands in magnetic semiconductors induces an extremely large angular response of magnetotransport. Taking a layered ferrimagnet, Mn3Si2Te6, and its derived compounds as a model system, we show that the topological band degeneracy, driven by chiral molecular orbital states, is lifted depending on spin orientation, which leads to a metal–insulator transition in the same ferrimagnetic phase. The resulting variation of angular magnetoresistance with rotating magnetization exceeds a trillion per cent per radian, which we call colossal angular magnetoresistance. Our findings demonstrate that magnetic nodal-line semiconductors are a promising platform for realizing extremely sensitive spin- and orbital-dependent functionalities.

物理学Physics

Quantum gas magnifier for sub-lattice-resolved imaging of 3D quantum systems

用于三维量子系统亚晶格分辨成像的量子气体放大器

▲ 作者：Luca Asteria, Henrik P. Zahn, Marcel N. Kosch, Klaus Sengstock & Christof Weitenberg

▲ 链接：

https://www.nature.com/articles/s41586-021-04011-2

▲ 摘要

在此，我们介绍了一种成像方法，在光学成像之前，物质波光学放大密度分布，在3D系统中实现2D亚晶格间距分辨率。通过结合分辨成像和磁共振技术对单个点阵点进行局部定位，我们展示了在3D系统中对2D局部信息和操作的完全可访问性。

我们利用高分辨率图像对光学晶格中的玻色-爱因斯坦凝聚进行了精确的热力学研究，并研究了热跳跃驱动下的热化动力学。子晶格分辨率是通过在晶格位内的猝灭动力学来证明的。

该方法为新量子多体体系的空间解析研究开辟了道路，包括奇异的晶格几何或亚波长晶格，并为原子种类的单原子分辨成像铺平了道路，而有效的激光冷却或深层光阱是不可用的，但实质上丰富了多体系统量子模拟的工具箱。

▲ Abstract

Here we introduce an imaging approach where matter wave optics magnifies the density distribution before optical imaging, allowing 2D sub-lattice-spacing resolution in three-dimensional (3D) systems. By combining the site-resolved imaging with magnetic resonance techniques for local addressing of individual lattice sites, we demonstrate full accessibility to 2D local information and manipulation in 3D systems. We employ the high-resolution images for precision thermodynamics of Bose–Einstein condensates in optical lattices as well as studies of thermalization dynamics driven by thermal hopping. The sub-lattice resolution is demonstrated via quench dynamics within the lattice sites. The method opens the path for spatially resolved studies of new quantum many-body regimes, including exotic lattice geometries or sub-wavelength lattices, and paves the way for single-atom-resolved imaging of atomic species, where efficient laser cooling or deep optical traps are not available, but which substantially enrich the toolbox of quantum simulation of many-body systems.

地球科学Geoscience

Mechanical forcing of the North American monsoon by orography

地形对北美季风的机械作用力

▲ 作者：William R. Boos & Salvatore Pascale

▲ 链接：

https://www.nature.com/articles/s41586-021-03978-2

▲ 摘要

在此，我们发现当墨西哥的马德雷山脉使温带急流偏转向赤道时，产生了北美核心季风，机械地迫使东移的上坡流提升温暖和潮湿的空气，产生对流降雨。

这些发现是基于对观测资料的动力和热力学结构的分析，全球气候模式整合和绝热驻波解。地表热通量确实是大气对流的先决条件，特别是在夏季下午，但这些热通量本身不足以产生观测到的最大降雨量。

我们的结果表明，北美核心季风应该被理解为机械强迫驻波中的对流增强地形降水，而不是典型的热力强迫热带季风。这意味着北美季风对过去和未来全球气候变化的响应，使急流与地形相互作用的趋势具有中心重要性。

▲ Abstract

Here we show that the core North American monsoon is generated when Mexico’s Sierra Madre mountains deflect the extratropical jet stream towards the Equator, mechanically forcing eastward, upslope flow that lifts warm and moist air to produce convective rainfall. These findings are based on analyses of dynamic and thermodynamic structures in observations, global climate model integrations and adiabatic stationary wave solutions. Land surface heat fluxes do precondition the atmosphere for convection, particularly in summer afternoons, but these heat fluxes alone are insufficient for producing the observed rainfall maximum. Our results indicate that the core North American monsoon should be understood as convectively enhanced orographic rainfall in a mechanically forced stationary wave, not as a classic, thermally forced tropical monsoon. This has implications for the response of the North American monsoon to past and future global climate change, making trends in jet stream interactions with orography of central importance.

人类学Anthropology

Triangulation supports agricultural spread of the Transeurasian languages

三角测量法支持了跨欧亚语言在农业上的传播

▲ 作者：Martine Robbeets, Remco Bouckaert, Matthew Conte, Alexander Savelyev, Tao Li, Deog-Im An, Ken-ichi Shinoda, Yinqiu Cui, Takamune Kawashima et al.

▲ 链接：

https://www.nature.com/articles/s41586-021-04108-8

▲ 摘要

在此，我们通过对遗传学、考古学和语言学进行“三角定位”来解决问题。我们报告了来自这些学科的广泛数据集，包括全面的跨欧亚农牧和基本词汇; 东北亚255处新石器-青铜器时代遗址的考古数据库; 以及来自韩国和日本早期谷物农民的古代基因组的收集，这些基因组补充了此前发表的东亚基因组。

我们对传统的“牧民假说”提出了挑战，证明了跨欧亚语言的共同祖先和原始传播可以追溯到新石器时代早期横跨东北亚的第一批农民，但自青铜时代以来，这种共同遗产被广泛的文化互动掩盖了。

除了在三个独立学科上取得了相当大的进步外，通过结合它们各自的证据，我们还表明，跨欧亚语系的早期传播是由农业推动的。

▲ Abstract

Here we address this question by ‘triangulating’ genetics, archaeology and linguistics in a unified perspective. We report wide-ranging datasets from these disciplines, including a comprehensive Transeurasian agropastoral and basic vocabulary; an archaeological database of 255 Neolithic–Bronze Age sites from Northeast Asia; and a collection of ancient genomes from Korea, the Ryukyu islands and early cereal farmers in Japan, complementing previously published genomes from East Asia. Challenging the traditional ‘pastoralist hypothesis, we show that the common ancestry and primary dispersals of Transeurasian languages can be traced back to the first farmers moving across Northeast Asia from the Early Neolithic onwards, but that this shared heritage has been masked by extensive cultural interaction since the Bronze Age. As well as marking considerable progress in the three individual disciplines, by combining their converging evidence we show that the early spread of Transeurasian speakers was driven by agriculture.