《科學》（20201030出版）一周論文導讀

編譯 | 李言

Science, 30 OCTOBER 2020, VOL 370, ISSUE 6516

《科學》2020年10月30日，第370卷，6516期

地球科學Geoscience

Surface deformation associated with fractures near the 2019 Ridgecrest earthquake sequence

與2019年裡齊克雷斯特地震序列相關的地表變形

▲ 作者：Xiaohua Xu, David T. Sandwell, Lauren A. Ward, Chris W. D. Milliner, Bridget R. Smith-Konter, et al.

▲ 連結：

https://science.sciencemag.org/content/370/6516/605

▲ 摘要

當代的地震災害模型依賴於對地殼中應變如何分布的理解，以及在活躍斷層的廣大區域中精確探測毫米級變形的能力。衛星雷達觀測顯示，在2019年裡齊克雷斯特地震序列周圍，有數百個之前未繪製的線性應變濃度（或裂縫）。

我們記錄並分析了其中169條裂縫的位移和寬度。雖然大多數裂縫是沿主構造應力（進積）方向位移的，但也有大量裂縫是沿相反方向位移的。我們開發了一個模型來解釋這些位移的存在和行為。

一個重要的可能是，許多進積構造應變是由許多先前存在的斷層上的摩擦滑動所調節的。

▲ Abstract

Contemporary earthquake hazard models hinge on an understanding of how strain is distributed in the crust and the ability to precisely detect millimeter-scale deformation over broad regions of active faulting. Satellite radar observations revealed hundreds of previously unmapped linear strain concentrations (or fractures) surrounding the 2019 Ridgecrest earthquake sequence. We documented and analyzed displacements and widths of 169 of these fractures. Although most fractures are displaced in the direction of the prevailing tectonic stress (prograde), a large number of them are displaced in the opposite (retrograde) direction. We developed a model to explain the existence and behavior of these displacements. A major implication is that much of the prograde tectonic strain is accommodated by frictional slip on many preexisting faults.

動物學Zoology

Origins and genetic legacy of prehistoric dogs

史前犬類的起源和遺產

▲ 作者：Anders Bergström, Laurent Frantz, Ryan Schmidt, Erik Ersmark, et al.

▲ 連結：

https://science.sciencemag.org/content/370/6516/557

▲ 摘要

狗是最早的家畜，但人們對它們的種群歷史以及與人類的聯繫知之甚少。

我們對27個古代狗的基因組進行了測序，發現所有的狗都有與現在的狼不同的一個共同祖先，自馴化以來，狼的基因流動有限，但狗和狼之間有大量的基因流動。

到1.1萬年前，至少有5種主要的血統出現了多樣化，這表明了舊石器時代犬類的深厚遺傳歷史。

與人類基因組的共同分析揭示了犬類種群歷史與人類相似的方面，包括非洲和早期農業歐洲的黎凡特族祖先族群。其他方面則有所不同，包括歐亞大陸西部和東部草原遊牧擴張的影響，以及新石器時代歐洲犬類祖先幾乎完全更替。

▲ Abstract

Dogs were the first domestic animal, but little is known about their population history and to what extent it was linked to humans. We sequenced 27 ancient dog genomes and found that all dogs share a common ancestry distinct from present-day wolves, with limited gene flow from wolves since domestication but substantial dog-to-wolf gene flow. By 11,000 years ago, at least five major ancestry lineages had diversified, demonstrating a deep genetic history of dogs during the Paleolithic. Coanalysis with human genomes reveals aspects of dog population history that mirror humans, including Levant-related ancestry in Africa and early agricultural Europe. Other aspects differ, including the impacts of steppe pastoralist expansions in West and East Eurasia and a near-complete turnover of Neolithic European dog ancestry.

量子科學Quantum Science

Parallel single-shot measurement and coherent control of solid-state spins below the diffraction limit

在衍射極限下的平行單次測量和固態自旋的相干控制

▲ 作者：Songtao Chen, Mouktik Raha, Christopher M. Phenicie, Salim Ourari, Jeff D. Thompson

▲ 連結：

https://science.sciencemag.org/content/370/6516/592

▲ 摘要

固態自旋缺陷是量子科學技術的一個很有前途的平臺。實現具有固態缺陷的更大尺度量子系統，需要對具有納米級分離的多個缺陷進行高保真控制，需要具有用於多量子位邏輯操作的強自旋自旋相互作用和產生糾纏態。

我們展示了一種光頻域多路復用技術，允許高保真初始化和單鏡頭自旋測量6個稀土（Er3+）離子，在一個單獨的矽光子晶體腔亞波長範圍內。我們還演示了亞波長控制相干自旋旋轉使用光學交流斯塔克位移。

我們的方法可以擴展到任意小分離的大量離子，是實現強相互作用的原子缺陷系綜的一步，在量子信息處理和多體動力學的基礎研究中有應用。

▲ Abstract

Solid-state spin defects are a promising platform for quantum science and technology. The realization of larger-scale quantum systems with solid-state defects will require high-fidelity control over multiple defects with nanoscale separations, with strong spin-spin interactions for multi-qubit logic operations and the creation of entangled states. We demonstrate an optical frequency-domain multiplexing technique, allowing high-fidelity initialization and single-shot spin measurement of six rare-earth (Er3+) ions, within the subwavelength volume of a single, silicon photonic crystal cavity. We also demonstrate subwavelength control over coherent spin rotations by using an optical AC Stark shift. Our approach may be scaled to large numbers of ions with arbitrarily small separation and is a step toward realizing strongly interacting atomic defect ensembles with applications to quantum information processing and fundamental studies of many-body dynamics.

Generation of helical topological exciton-polaritons

螺旋拓撲激子-極化激子的產生

▲ 作者：Wenjing Liu, Zhurun Ji, Yuhui Wang, Gaurav Modi, Minsoo Hwang, Biyuan Zheng, et al.

▲ 連結：

https://science.sciencemag.org/content/370/6516/600

▲ 摘要

拓撲光子學在強耦合光物質系統提供了製造抗混亂和缺陷的魯棒性可調諧光學器件的可能性。拓撲極化子，即雜化雷射子準粒子，已被提出用於演示無散射的手性傳播，但迄今為止，他們的實驗實現是在深低溫和強磁場下。

我們證明了在無外加磁場的情況下，在單層WS2激子中螺旋拓撲極化子可達200 k，這些激子耦合在一個受偽時反對稱性保護的非平凡光子晶體上。

我們驗證了拓撲極極化子的螺旋性質，其中具有相反螺旋性的極極化子被輸送到相反的方向。拓撲螺旋極化激子提供了一個平臺，開發穩健的和可調的極化激子自旋電子器件，用於經典和量子信息處理應用。

▲ Abstract

Topological photonics in strongly coupled light-matter systems offer the possibility for fabricating tunable optical devices that are robust against disorder and defects. Topological polaritons, i.e., hybrid exciton-photon quasiparticles, have been proposed to demonstrate scatter-free chiral propagation, but their experimental realization to date has been at deep cryogenic temperatures and under strong magnetic fields. We demonstrate helical topological polaritons up to 200 kelvin without external magnetic field in monolayer WS2 excitons coupled to a nontrivial photonic crystal protected by pseudo time-reversal symmetry. The helical nature of the topological polaritons, where polaritons with opposite helicities are transported to opposite directions, is verified. Topological helical polaritons provide a platform for developing robust and tunable polaritonic spintronic devices for classical and quantum information-processing applications.

材料科學Material Science

Metal-organic magnets with large coercivity and ordering temperatures up to 242°C

具有強矯頑力和溫度可高達242°C的金屬有機磁體

▲ 作者：Panagiota Perlepe, Itziar Oyarzabal, Aaron Mailman, Morgane Yquel, et al.

▲ 連結：

https://science.sciencemag.org/content/370/6516/587

▲ 摘要

從無機材料（例如氧化物、稀土和金屬間化合物）中提取的磁體是現代技術應用的關鍵組成部分。

儘管在廣泛的應用領域取得了相當大的成功，這些無機磁體仍存在一些缺點，包括製造成本高昂、某些組成元素的可用性有限、密度高和化學可調性差。具有前景的新一代磁體設計策略依賴於豐富的金屬離子和廉價的有機配體的多功能配位化學。

根據這一方法，我們報告了通過合成後還原含有鉻金屬離子和吡嗪構建塊的預組裝配位網絡來合成輕質分子基磁體的簡單有效方法。由此產生的金屬有機鐵磁體具有臨界溫度高達242℃和7500 OE的室溫矯頑力。

▲ Abstract

Magnets derived from inorganic materials (e.g., oxides, rare-earth–based, and intermetallic compounds) are key components of modern technological applications. Despite considerable success in a broad range of applications, these inorganic magnets suffer several drawbacks, including energetically expensive fabrication, limited availability of certain constituent elements, high density, and poor scope for chemical tunability. A promising design strategy for next-generation magnets relies on the versatile coordination chemistry of abundant metal ions and inexpensive organic ligands. Following this approach, we report the general, simple, and efficient synthesis of lightweight, molecule-based magnets by postsynthetic reduction of preassembled coordination networks that incorporate chromium metal ions and pyrazine building blocks. The resulting metal-organic ferrimagnets feature critical temperatures up to 242°C and a 7500-oersted room-temperature coercivity.

Atomic-scale microstructure of metal halide perovskite

金屬滷化物鈣鈦礦的原子級微觀結構

▲ 作者：Mathias Uller Rothmann, Judy S. Kim, Juliane Borchert, Kilian B. Lohmann, et al.

▲ 連結：

https://science.sciencemag.org/content/370/6516/eabb5940

▲ 摘要

有機-無機雜化鈣鈦礦作為太陽能材料具有很高的應用潛力，但其微觀特性仍不清楚。

原子解析度掃描透射電子顯微鏡已經為晶體太陽電池材料提供了許多有價值的信息，我們使用這種方法成功地在低劑量的電子輻照下成像了甲脒鉛碘化物 [CH(NH2)2PbI3]薄膜。

這些圖像顯示了一個高度有序的原子排列的晶界和相干鈣鈦礦/ PbI2界面，與一個驚人的無長程無序的晶體。

我們發現，光束誘導的鈣鈦礦降解導致了一種初始損失，甲醯胺離子[CH(NH2)2+]，留下部分未佔據的鈣鈦礦晶格，這解釋了這些材料不尋常的再生特性。我們進一步觀察了對齊點缺陷和攀爬離解位錯。因此，我們的發現為技術上重要的滷化鉛鈣鈦礦提供了原子層面的理解。

▲ Abstract

Hybrid organic-inorganic perovskites have high potential as materials for solar energy applications, but their microscopic properties are still not well understood. Atomic-resolution scanning transmission electron microscopy has provided invaluable insights for many crystalline solar cell materials, and we used this method to successfully image formamidinium lead triiodide [CH(NH2)2PbI3] thin films with a low dose of electron irradiation. Such images reveal a highly ordered atomic arrangement of sharp grain boundaries and coherent perovskite/PbI2 interfaces, with a striking absence of long-range disorder in the crystal. We found that beam-induced degradation of the perovskite leads to an initial loss of formamidinium [CH(NH2)2+] ions, leaving behind a partially unoccupied perovskite lattice, which explains the unusual regenerative properties of these materials. We further observed aligned point defects and climb-dissociated dislocations. Our findings thus provide an atomic-level understanding of technologically important lead halide perovskites.