20 February 2024 | Open Access Diffractive optical computing in free space Optical computing via free-space-based structured optical materials allows to access optical information without the need for preprocessing or optoelectronic conversion. In this Perspective, the authors describe opportunities and challenges in their use for optical computing, information processing, computational imaging and sensing. Jingtian Hu, Deniz Mengu & Aydogan Ozcan Article 20 February 2024 | Open Access Enhancing detection of topological order by local error correction Detection of topological phases in experiments is challenging, especially in the presence of incoherent noise. Cong et al. introduce a novel method combining error correction and renormalization-group flow and apply it to characterization of quantum spin liquid phases realized in a Rydberg-atom simulator. Iris Cong, Nishad Maskara & Mikhail D. Lukin Article 19 February 2024 | Open Access Cooperative Cu/azodiformate system-catalyzed allylic C–H amination of unactivated internal alkenes directed by aminoquinoline The oxidative intermolecular amination of C-H bonds represents a straightforward method to construct aliphatic allylic amines. However, the utilization of widely available internal alkenes remains a synthetic challenge. Here, the authors present a regioselective Cu-catalyzed oxidative allylic C-H amination of internal olefins with azodiformates. Le Wang, Cheng-Long Wang & Shu-Yu Zhang Article 19 February 2024 | Open Access Liquid Madelung energy accounts for the huge potential shift in electrochemical systems Electrode potential in any electrochemical systems has long been discussed by classical Debye-Hückel theory which holds only under extremely dilute concentrations. Here, the authors establish the concept ‘liquid Madelung potential’ to comprehensively describe the potential shift at practical concentrations. Norio Takenaka, Seongjae Ko & Atsuo Yamada Article 19 February 2024 | Open Access Stable water splitting using photoelectrodes with a cryogelated overlayer Photoelectrodes made of earth-abundant materials can contribute to low-cost and carbon-free hydrogen production, but suffer from a short lifetime. Here the authors report cryogel overlayer to increase the operation time of the device by regulating evolving hydrogen bubble dynamics. Byungjun Kang, Jeiwan Tan & Hyungsuk Lee Article 19 February 2024 | Open Access Current-induced switching of a van der Waals ferromagnet at room temperature Fe3GaTe2 is a van der Waals material with a Curie temperature well above room temperature, making it an attractive material for integration into spintronic devices. Here, Kajale et al demonstrate spin-orbit torque induced switching of the magnetization of Fe3GaTe2, above room temperature, using a Pt spin Hall layer. Shivam N. Kajale, Thanh Nguyen & Deblina Sarkar Article 19 February 2024 | Open Access Realization of all-band-flat photonic lattices Here the authors experimentally realized a systematic approach to synthesize arbitrary-size two-dimensional all-band-flat photonic lattices, which pave a route for investigating flat-band related physics such as slow-light, nonlinear breathing, and dispersionless image transmission. Jing Yang, Yuanzhen Li & Fei Gao Article 19 February 2024 | Open Access Molecular co-assembled strategy tuning protein conformation for cartilage regeneration The assembly of oligopeptide and polypeptide molecules can reconstruct various ordered advanced structures. Here the authors develop a “molecular velcro”-inspired amphiphilic supramolecular co-assembly strategy, which improves the mechanical strength and cartilaginous regeneration efficiency through conformation transition. Chengkun Zhao, Xing Li & Yong Sun Article 19 February 2024 | Open Access Complexation-driven assembly of imine-linked helical receptors showing adaptive folding and temperature-dependent guest selection The development of synthetic receptors capable of selectively binding monosaccharides is highly challenging. Here, authors present the efficient synthesis of these receptors based on foldamers, achieved through complexation-induced equilibrium shifting. Geunmoo Song, Seungwon Lee & Kyu-Sung Jeong Article 19 February 2024 | Open Access VO2 memristor-based frequency converter with in-situ synthesize and mix for wireless internet-of-things Frequency converters for wireless internet of things applications typically require separate circuits for different functions, causing energy and performance inefficiencies. Using an epitaxially grown VO2 memristor array, Liu et al. present a frequency converter with in-situ frequency synthesis and mix functionality. Chang Liu, Pek Jun Tiw & Yuchao Yang Article 19 February 2024 | Open Access Kirkendall effect-induced uniform stress distribution stabilizes nickel-rich layered oxide cathodes Nickel-rich layered oxide cathodes offer high energy density yet suffer from mechanical degradation during (de)lithiation. Here, the authors present a strategy that leverages the Kirkendall effect to equalize stress within the cathode particles, thereby stabilizing their structure and enhancing the cycling stability. Ziyao Gao, Chenglong Zhao & Baohua Li Article 19 February 2024 | Open Access A high-current hydrogel generator with engineered mechanoionic asymmetry Mechanoelectric energy conversion is a potential solution for the power supply of soft devices, but the low current output for low frequency motions limits its applicability. Here, the authors report a hydrogel generator with mechanoionic current generation amplified by orders of magnitudes and its application as controlled drug-releasing system for wound healing. Hongzhen Liu, Xianglin Ji & Lizhi Xu Article 19 February 2024 | Open Access Metal-free photocatalytic cross-electrophile coupling enables C1 homologation and alkylation of carboxylic acids with aldehydes Enhancing the sp3-hybridized character of molecular structures in drug discovery is paramount. Here, the authors introduce a deoxygenative cross-electrophile coupling technique that pairs easily accessible carboxylic acid-derived redox-active esters with aldehyde sulfonyl hydrazones, employing Eosin Y as an organophotocatalyst under visible light irradiation. Stefano Bonciolini, Antonio Pulcinella & Timothy Noël Article 19 February 2024 | Open Access Achieving environmental stability in an atomically thin quantum spin Hall insulator via graphene intercalation Topological states in atomically thin quantum spin Hall insulators suffer from instability against environmental factors. Here, the authors devise a strategy to preserve topologically protected states in monolayer indenene through graphene intercalation. Cedric Schmitt, Jonas Erhardt & Ralph Claessen Article 19 February 2024 | Open Access Highly anisotropic Fe3C microflakes constructed by solid-state phase transformation for efficient microwave absorption Fe3C microflakes with high magnetic anisotropy are prepared through solid-state phase transformation and electrochemical dealloying. The magnetic anisotropy can be tuned by adjusting the morphology, resulting in optimized ferromagnetic resonance behavior for microwave absorption Rongzhi Zhao, Tong Gao & Gaowu Qin Article 19 February 2024 | Open Access Stenus-inspired, swift, and agile untethered insect-scale soft propulsors Inspired by the swift swingable abdomen, conducting canals, and body setae of Stenus comma, the authors present a swift, agile untethered insect-scale soft propulsor, offering new insights into systematically bio-inspired artificial soft robots. Xingxing Ke, Haochen Yong & Zhigang Wu Article 19 February 2024 | Open Access Self-supervised dynamic learning for long-term high-fidelity image transmission through unstabilized diffusive media This work introduces a cutting-edge technique to overcome dynamic scattering challenges in long-distance multimode fiber transmission, achieving >99.9% accuracy for 1024 modes over 1 km, hence promises applications in diverse scattering scenarios. Ziwei Li, Wei Zhou & Qionghai Dai Article 17 February 2024 | Open Access Iron-catalyzed fluoroalkylative alkylsulfonylation of alkenes via radical-anion relay Stoichiometric amounts of metal reductant and the requirement of a directing group limit the application of transition metal-catalyzed reductive difunctionalization of alkenes with alkyl halides. Here, the authors report a reductive difunctionalization of alkenes via a radical-anion relay with Na2S2O4 as both reductant and sulfone-source. Xiaoya Hou, Hongchi Liu & Hanmin Huang Review Article 17 February 2024 | Open Access Challenges and recent advancements in the synthesis of α,α-disubstituted α-amino acids α,α-Disubstituted α-amino acids (α-AAs) have improved properties compared to other amino acids. Here, the authors provide an overview of the recent advancements since 2015 and discuss existing challenges for their synthesis. Yu Zhang, Jaro Vanderghinste & Shoubhik Das Article 17 February 2024 | Open Access Oxygen-tolerant CO2 electroreduction over covalent organic frameworks via photoswitching control oxygen passivation strategy Direct use of flue gas for the electrocatalytic CO2 reduction reaction is desirable but severely limited by the thermodynamically favorable oxygen reduction reaction. Here the authors report an oxygen passivation strategy to improve electrocatalytic CO2 reduction reaction under aerobic conditions using a covalent organic frameworks with a photoswitching unit. Hong-Jing Zhu, Duan-Hui Si & Yuan-Biao Huang Article 17 February 2024 | Open Access Evidence for Topological Protection Derived from Six-Flux Composite Fermions Huang et al. study fractional quantum Hall (fQH) states in high-quality GaAs/AlGaAs samples. They report evidence for a fQH state at filling factor ν = 9/11, which they associate with the formation of six-flux composite fermions. Haoyun Huang, Waseem Hussain & G. A. Csáthy Article 17 February 2024 | Open Access Promoting high-voltage stability through local lattice distortion of halide solid electrolytes Solid electrolytes play a crucial role as ion conductors and separator between electrodes in all-solid-state batteries. Here, the authors report a high-entropy halide solid electrolyte, which reveals the structure evolution with the increasing configurational entropy and improves the high-voltage stability. Zhenyou Song, Tengrui Wang & Wei Luo Article 17 February 2024 | Open Access Robust temporal adiabatic passage with perfect frequency conversion between detuned acoustic cavities Phase matching is pivotal for realizing complete energy transfer for classical waves. Here, authors propose temporal quasi-phase matching method and realize robust and complete energy transfer between arbitrarily detuned acoustic cavities by combing the concept of stimulated Raman adiabatic passage. Zhao-Xian Chen, Yu-Gui Peng & Yan-Qing Lu Article 17 February 2024 | Open Access Circular olefin copolymers made de novo from ethylene and α-olefins Although several advances have been made in chemical Polyethylene (PE) re- and upcycling, energy-efficient and selective catalytic processes are still lacking. Here, the authors show coupling of an industrially relevant coordination copolymerization olefins with a functionalized chain-transfer agent, followed by modular assembly of the resulting telechelic polyolefin building blocks by polycondensation to afford ester-linked PE-based random and block copolymers which exhibit full chemical circularity. Xing-Wang Han, Xun Zhang & Yong Tang Article 17 February 2024 | Open Access A compressive hyperspectral video imaging system using a single-pixel detector The authors showcase a video-rate hyperspectral imager based on a single-pixel photodetector that can achieve high-throughput hyperspectral video recording at a low bandwidth. Specifically, they propose a joint spatial-spectral encoding scheme which can encode the scene into highly compressed single-pixel measurements and obtain temporal correlation at the same time. Yibo Xu, Liyang Lu & Kevin F. Kelly Article 17 February 2024 | Open Access Continuous ultraviolet to blue-green astrocomb Astrocombs serve as precision calibrators for astrophysical spectrographs by providing a regular sequence of optical lines on a multi-GHz grid. Here, the authors report the first broadband astrocomb in the UV to blue-green spectral region, where stellar absorption lines are most abundant. Yuk Shan Cheng, Kamalesh Dadi & Derryck T. Reid Article 17 February 2024 | Open Access Tuning ferroelectric phase transition temperature by enantiomer fraction The enantiomer fraction strategy can achieve continuous control of the phase transition temperature, chiroptical properties, SHG intensity and other properties of chiral two-dimensional lead bromide ferroelectrics. Chang-Chun Fan, Cheng-Dong Liu & Wen Zhang Article 17 February 2024 | Open Access CALPHAD accelerated design of advanced full-Zintl thermoelectric device Based on the CALPHAD method, authors propose an effective screening strategy for thermoelectric contact materials, realizing a high efficiency of ~11% (at ∆T = 430 K) for the full-Zintl phase thermoelectric device. Li Yin, Xiaofang Li & Qian Zhang Article 17 February 2024 | Open Access Elucidation of the role of metals in the adsorption and photodegradation of herbicides by metal-organic frameworks In this study, the authors explored the correlation between the structure and optoelectronic properties of metal organic frameworks for the removal of a harmful herbicide from water. Nan Chieh Chiu, Jacob M. Lessard & Kyriakos C. Stylianou Article 17 February 2024 | Open Access Tunable positions of Weyl nodes via magnetism and pressure in the ferromagnetic Weyl semimetal CeAlSi Topological semimetals with space-inversion and time-reversal symmetry breaking have attracted attention recently. Here, using a combination of experimental techniques and calculations, the authors demonstrate the tunability of the Weyl nodes via magnetism and pressure in the ferromagnetic Weyl semimetal CeAlSi. Erjian Cheng, Limin Yan & Bernd Büchner