《自然》（20240620）一周論文導讀

編譯｜馮維維

Nature, 20 June 2024, Volume 630 Issue 8017

《自然》, 2024年6月20日，第630卷，8017期

物理學Physics

A secondary atmosphere on the rocky exoplanet 55 Cancri e

系外行星巨蟹座55e上的大氣

▲ 作者：Renyu Hu, Aaron Bello-Arufe, Michael Zhang, Kimberly Paragas, Mantas Zilinskas, Christiaan van Buchem, Michael Bess, Jayshil Patel, Yuichi Ito, Mario Damiano, Markus Scheucher, Apurva V. Oza, Heather A. Knutson, Yamila Miguel, Diana Dragomir, Alexis Brandeker & Brice-Olivier Demory

▲ 鏈接：

https://www.nature.com/articles/s41586-024-07432-x

▲ 摘要：

描繪巖石系外行星的特征是天文學的中心目標，然而迄今為止，在巖石系外行星上尋找大氣的結果要么是大氣質量的嚴格上限，要么是不確定的結果。相當于1.95個地球半徑和8.8個地球質量的行星——巨蟹座55 e（以下簡稱55Cnc e），主要由巖石組成，平衡溫度約為2000 K，可能有一個揮發性的包層（包含由C、H、O、N、S和P元素組合而成的分子），占其半徑的百分之幾。

研究者利用透射光譜對該行星進行了廣泛的觀測，并在寬光度波段測量了其熱輻射。這些觀測不支持原始H2/ he主導的大氣，但不能最終確定該行星是否有次級大氣。

研究者報道了由詹姆斯韋布太空望遠鏡獲得的行星4 ~ 12μm的熱發射光譜。測量結果排除了這顆行星是一個熔巖世界，被由蒸發巖石組成的稀薄大氣所覆蓋的可能性，表明它是一個真正的揮發性大氣，可能富含二氧化碳或一氧化碳。這種大氣可以從巖漿海洋中釋放出來，并由巖漿海洋維持。

▲ Abstract：

Characterizing rocky exoplanets is a central aim of astronomy, and yet the search for atmospheres on rocky exoplanets has so far resulted in either tight upper limits on the atmospheric mass or inconclusive results. The 1.95REarth and 8.8MEarth planet 55?Cancri?e (abbreviated 55?Cnc?e), with a predominantly rocky composition and an equilibrium temperature of around 2,000?K, may have a volatile envelope (containing molecules made from a combination of C, H, O, N, S and P elements) that accounts for up to a few percent of its radius. The planet has been observed extensively with transmission spectroscopy and its thermal emission has been measured in broad photometric bands. These observations disfavour a primordial H2/He-dominated atmosphere but cannot conclusively determine whether the planet has a secondary atmosphere. Here we report a thermal emission spectrum of the planet obtained by the NIRCam and MIRI instruments aboard the James Webb Space Telescope (JWST) from 4 to 12?μm. The measurements rule out the scenario in which the planet is a lava world shrouded by a tenuous atmosphere made of vaporized rock and indicate a bona fide volatile atmosphere that is probably rich in CO2 or CO. This atmosphere can be outgassed from and sustained by a magma ocean.

A site-resolved two-dimensional quantum simulator with hundreds of trapped ions

具有數百個捕獲離子的位置分辨二維量子模擬器

▲ 作者：S.-A. Guo, Y.-K. Wu, J. Ye, L. Zhang, W.-Q. Lian, R. Yao, Y. Wang, R.-Y. Yan, Y.-J. Yi, Y.-L. Xu, B.-W. Li, Y.-H. Hou, Y.-Z. Xu, W.-X. Guo, C. Zhang, B.-X. Qi, Z.-C. Zhou, L. He & L.-M. Duan

▲ 鏈接：

https://www.nature.com/articles/s41586-024-07459-0

▲ 摘要：

大量子位容量和單個讀出能力是大規模量子計算和模擬的兩個關鍵要求。作為量子信息處理的主要物理平臺之一，離子阱已經在一維保羅阱中實現了數十個具有位置分辨讀出的離子的量子模擬，在二維 Penning阱中實現了數百個具有全局可觀測值的離子的量子模擬。

然而，將這兩個功能集成到一個系統中仍然非常具有挑戰性。研究者報道了512個離子在二維維格納晶體中的穩定捕獲及其橫向運動的邊帶冷卻。

研究者利用單次測量中的位置分辨率，在準絕熱制備的基態中觀察到豐富的空間相關模式，可以通過將測量的雙自旋相關與計算的集體聲子模式以及經典模擬退火進行比較，來驗證量子模擬結果。

研究進一步探討了Ising模型在橫向場中的猝滅動力學，以演示量子采樣任務。該研究為模擬經典棘手的量子動力學和使用二維離子阱量子模擬器運行有噪聲的中等規模量子算法鋪平了道路。

▲ Abstract：

A large qubit capacity and an individual readout capability are two crucial requirements for large-scale quantum computing and simulation. As one of the leading physical platforms for quantum information processing, the ion trap has achieved a quantum simulation of tens of ions with site-resolved readout in a one-dimensional Paul trap and of hundreds of ions with global observables in a two-dimensional (2D) Penning trap. However, integrating these two features into a single system is still very challenging. Here we report the stable trapping of 512 ions in a 2D Wigner crystal and the sideband cooling of their transverse motion. Enabled by the site resolution in the single-shot measurement, we observe rich spatial correlation patterns in the quasi-adiabatically prepared ground states, which allows us to verify quantum simulation results by comparing the measured two-spin correlations with the calculated collective phonon modes and with classical simulated annealing. We further probe the quench dynamics of the Ising model in a transverse field to demonstrate quantum sampling tasks. Our work paves the way for simulating classically intractable quantum dynamics and for running noisy intermediate-scale quantum algorithms using 2D ion trap quantum simulators.

化學物理Chemical Physics

Acceleration of radiative recombination for efficient perovskite LEDs

加速高效鈣鈦礦LED輻射復合

▲ 作者：Mengmeng Li, Yingguo Yang, Zhiyuan Kuang, Chenjie Hao, Saixue Wang, Feiyue Lu, Zhongran Liu, Jinglong Liu, Lingjiao Zeng, Yuxiao Cai, Yulin Mao, Jingshu Guo, He Tian, Guichuan Xing, Yu Cao, Chao Ma, Nana Wang, Qiming Peng, Lin Zhu, Wei Huang & Jianpu Wang

▲ 鏈接：

https://www.nature.com/articles/s41586-024-07460-7

▲ 摘要：

平板顯示器和固態照明應用對更高效、更亮的薄膜發光二極管（LED）的需求日益增長，這推動了對三維鈣鈦礦的研究。這些材料表現出高電荷遷移率和低量子效率下降，使它們成為實現具有增強亮度的高效LED的有希望的候選者。

為了提高led的效率，在促進輻射復合的同時盡量減少非輻射復合是至關重要的。各種鈍化策略已被用于降低三維鈣鈦礦薄膜的缺陷密度，接近單晶的水平。然而，緩慢的輻射（雙分子）重組使三維鈣鈦礦的光致發光量子效率（PLQEs）低于80%，導致LED器件的外部量子效率（EQEs）低于25%。

研究者提出了一種雙添加劑結晶方法，可以形成高效三維鈣鈦礦，實現了96%的卓越PLQE。這種方法促進了四邊形FAPbI3鈣鈦礦的形成，以其高激子結合能而聞名，有效地加速了輻射復合。

研究實現了具有創紀錄峰值EQE為32.0%的鈣鈦礦LED，即使在100 mA cm?2的高電流密度下，效率仍然大于30.0%。這些發現為推進高效、高亮度鈣鈦礦LED的發展提供了有價值的見解。

▲ Abstract：

The increasing demands for more efficient and brighter thin-film light-emitting diodes (LEDs) in flat-panel display and solid-state lighting applications have promoted research into three-dimensional (3D) perovskites. These materials exhibit high charge mobilities and low quantum efficiency droop, making them promising candidates for achieving efficient LEDs with enhanced brightness. To improve the efficiency of LEDs, it is crucial to minimize nonradiative recombination while promoting radiative recombination. Various passivation strategies have been used to reduce defect densities in 3D perovskite films, approaching levels close to those of single crystals. However, the slow radiative (bimolecular) recombination has limited the photoluminescence quantum efficiencies (PLQEs) of 3D perovskites to less than 80%, resulting in external quantum efficiencies (EQEs) of LED devices of less than 25%. Here we present a dual-additive crystallization method that enables the formation of highly efficient 3D perovskites, achieving an exceptional PLQE of 96%. This approach promotes the formation of tetragonal FAPbI3 perovskite, known for its high exciton binding energy, which effectively accelerates the radiative recombination. As a result, we achieve perovskite LEDs with a record peak EQE of 32.0%, with the efficiency remaining greater than 30.0% even at a high current density of 100?mA?cm?2. These findings provide valuable insights for advancing the development of high-efficiency and high-brightness perovskite LEDs.

Atomic dynamics of electrified solid–liquid interfaces in liquid-cell TEM

液電池TEM中帶電固液界面的原子動力學

▲ 作者：Qiubo Zhang, Zhigang Song, Xianhu Sun, Yang Liu, Jiawei Wan, Sophia B. Betzler, Qi Zheng, Junyi Shangguan, Karen C. Bustillo, Peter Ercius, Prineha Na

▲ 鏈接：

https://www.nature.com/articles/s41586-024-07479-w

▲ 摘要：

帶電固液界面在與能源、生物和地球化學相關的各種電化學過程中起著關鍵作用。帶電界面上的電子和質量傳遞可能導致結構改變，從而顯著影響反應途徑。例如，電催化劑在反應過程中的表面重組會對催化機理和反應產物產生實質性的影響。

盡管它很重要，但直接探測電偏置下固液界面的原子動力學是具有挑戰性的，因為它被埋在液體電解質中，而且目前通過液體進行原位成像的技術空間分辨率有限。研究者開發了用于透射電子顯微鏡（TEM）的先進聚合物電化學液體電池，能夠直接監測銅催化二氧化碳電還原反應（CO2ERs）過程中ESLIs的原子動力學。

研究者觀察揭示了一個波動的液體狀無定形界面。它發生可逆的晶—非晶結構轉變，并沿通電銅表面流動，從而通過界面層介導結晶銅表面重構和質量損失。實時觀察和理論計算的結合揭示了由電荷激活的電解質表面反應引起的非晶化介導的重組機制。通過利用原位成像能力，該的結果為探索原子動力學及其在涉及ESLIs的廣泛系統中的影響提供了許多機會。

▲ Abstract：

Electrified solid–liquid interfaces (ESLIs) play a key role in various electrochemical processes relevant to energy, biology and geochemistry. The electron and mass transport at the electrified interfaces may result in structural modifications that markedly influence the reaction pathways. For example, electrocatalyst surface restructuring during reactions can substantially affect the catalysis mechanisms and reaction products. Despite its importance, direct probing the atomic dynamics of solid–liquid interfaces under electric biasing is challenging owing to the nature of being buried in liquid electrolytes and the limited spatial resolution of current techniques for in situ imaging through liquids. Here, with our development of advanced polymer electrochemical liquid cells for transmission electron microscopy (TEM), we are able to directly monitor the atomic dynamics of ESLIs during copper (Cu)-catalysed CO2 electroreduction reactions (CO2ERs). Our observation reveals a fluctuating liquid-like amorphous interphase. It undergoes reversible crystalline–amorphous structural transformations and flows along the electrified Cu surface, thus mediating the crystalline Cu surface restructuring and mass loss through the interphase layer. The combination of real-time observation and theoretical calculations unveils an amorphization-mediated restructuring mechanism resulting from charge-activated surface reactions with the electrolyte. Our results open many opportunities to explore the atomic dynamics and its impact in broad systems involving ESLIs by taking advantage of the in situ imaging capability.

化學Chemistry

Reproducible graphene synthesis by oxygen-free chemical vapour deposition

無氧化學氣相沉積法合成可再生石墨烯

▲ 作者：Jacob Amontree, Xingzhou Yan, Christopher S. DiMarco, Pierre L. Levesque, Tehseen Adel, Jordan Pack, Madisen Holbrook, Christian Cupo, Zhiying Wang, Dihao Sun, Adam J. Biacchi, Charlezetta E. Wilson-Stokes, Kenji Watanabe, Takashi Taniguchi, Cory R. Dean, Angela R. Hight Walker, Katayun Barmak, Richard Martel & James Hone

▲ 鏈接：

https://www.nature.com/articles/s41586-024-07454-5

▲ 摘要：

化學氣相沉積（CVD）在銅上合成石墨烯的方法自首次演示以來已被廣泛采用。然而，CVD生長的石墨烯在基礎科學和應用中的廣泛應用一直受到可重復性和質量挑戰的阻礙。我們發現微量氧是決定低壓CVD生長石墨烯的生長軌跡和質量的關鍵因素。

無氧化學氣相沉積（OF-CVD）合成速度快，可重復性高，動力學可以用緊湊的模型來描述，而添加微量氧會抑制成核和緩慢/不完全生長。通過表面污染、拉曼D峰的出現和電導率的降低來評估氧對石墨烯質量的影響。在無氧條件下生長的外延石墨烯是無污染的，沒有可檢測到的D峰。

經過干燥轉移和氮化硼封裝后，其室溫電輸運行為接近于剝離的石墨烯。石墨門控器件表現出良好的整數和分數量子霍爾效應。通過強調消除微量氧的重要性，新研究作為今后CVD系統的設計和運行提供了指導。由OF-CVD 合成的可重復性和質量的提高將廣泛影響石墨烯的基礎研究和應用。

▲ Abstract：

Chemical vapour deposition (CVD) synthesis of graphene on copper has been broadly adopted since the first demonstration of this process. However, widespread use of CVD-grown graphene for basic science and applications has been hindered by challenges with reproducibility and quality. Here we identify trace oxygen as a key factor determining the growth trajectory and quality for graphene grown by low-pressure CVD. Oxygen-free chemical vapour deposition (OF-CVD) synthesis is fast and highly reproducible, with kinetics that can be described by a compact model, whereas adding trace oxygen leads to suppressed nucleation and slower/incomplete growth. Oxygen affects graphene quality as assessed by surface contamination, emergence of the Raman D peak and decrease in electrical conductivity. Epitaxial graphene grown in oxygen-free conditions is contamination-free and shows no detectable D peak. After dry transfer and boron nitride encapsulation, it shows room-temperature electrical-transport behaviour close to that of exfoliated graphene. A graphite-gated device shows well-developed integer and fractional quantum Hall effects. By highlighting the importance of eliminating trace oxygen, this work provides guidance for future CVD system design and operation. The increased reproducibility and quality afforded by OF-CVD synthesis will broadly influence basic research and applications of graphene.

Work hardening in colloidal crystals

膠體晶體的加工硬化

▲ 作者：Seongsoo Kim, Ilya Svetlizky, David A. Weitz & Frans Spaepen

▲ 鏈接：

https://www.nature.com/articles/s41586-024-07453-6

▲ 摘要：

膠體晶體表現出有趣的特性，在許多方面與它們的原子對應物相似。它們具有相同的晶體結構，經歷相同的相變，并具有相同的晶體缺陷。研究者們發現硬球膠體晶體表現出加工硬化。此外，盡管它們很柔軟，但膠體晶體的抗剪強度可以增加并接近晶體的理論極限，這是迄今為止很少有其他材料達到的值。

他們使用共聚焦顯微鏡顯示，膠體晶體的強度隨著位錯密度的增加而增加，并最終達到原子材料的經典泰勒縮放行為，盡管硬球相互作用缺乏原子相互作用的復雜性。

研究證明了泰勒硬化是通過位錯結的形成而產生的。然而，泰勒硬化機制僅在瞬態階段之后才建立起來，當膠體晶體變得如此堅硬，以至于應變被定位在一個薄的邊界層內時，它就停止了，在這個邊界層中，滑移是由位錯的非常規運動引起的。盡管膠體晶體和原子晶體在粒度和剪切模量上有許多數量級的差異，但它們之間驚人的相似表明加工硬化的普遍性。

▲ Abstract：

Colloidal crystals exhibit interesting properties that are in many ways analogous to their atomic counterparts. They have the same crystal structures, undergo. Here we show that hard-sphere colloidal crystals exhibit work hardening. Moreover, despite their softness, the shear strength of colloidal crystals can increase and approach the theoretical limit for crystals, a value reached in very few other materials so far. We use confocal microscopy to show that the strength of colloidal crystals increases with dislocation density, and ultimately reaches the classic Taylor scaling behaviour for atomic materials, although hard-sphere interactions lack the complexity of atomic interactions. We demonstrate that Taylor hardening arises through the formation of dislocation junctions. The Taylor hardening regime, however, is established only after a transient phase, and it ceases when the colloidal crystals become so hard that the strain is localized within a thin boundary layer in which slip results from an unconventional motion of dislocations. The striking resemblance between colloidal and atomic crystals, despite the many orders of magnitude difference in particle size and shear modulus, demonstrates the universality of work hardening.