Physics

The Goos–Hänchen-like (GH) shift of electron wavepackets at potential interfaces provides a powerful method for probing the properties of quantum materials. In this work, we theoretically investigate the spin- and valley-resolved GH shift in a monolayer of jacutingaite (Pt2HgSe3), a quantum spin Hall insulator, subjected to both a perpendicular electric field and off-resonant circularly polarized light. Using a low-energy effective Hamiltonian and a scattering formalism, we calculate the lateral displacement of transmitted electron beams across a finite barrier. Our results demonstrate that external fields can induce a nearly perfect spin- and valley-filtering effect and a fundamental electric-optical duality. Unlike simpler Dirac systems, such as graphene, where the GH shift typically exhibits a single resonant structure, the multi-gap Kane–Mele physics of jacutingaite gives rise to a unique multi-resonance hierarchy. Our central finding is revealed in energy–angle phase-space maps of the total GH shift, which exhibit prominent resonance ridges of giant displacement. We demonstrate that the pattern and structure of these contours serve as a distinct macroscopic fingerprint for the material’s underlying topological phases. This establishes the measurement of the GH shift as a sensitive tool for topological metrology, offering a clear experimental pathway for identifying microscopic topological phase transitions through macroscopic transport signatures.

Using density functional theory combined with thermochemical data, we analyze the formation of native and carbon-related defects in yttrium aluminum garnet (YAG) grown in a CO-containing atmosphere. The concentrations of various defect species in as-grown YAG are computed as functions of the partial pressures of CO, CO2, and O2. Under reducing conditions, carbon preferentially forms negatively charged CO defects, whereas positively charged CAl defects at the tetrahedral 24(d) positions dominate under oxidizing conditions. Only a small fraction of carbon-related defects (approximately 1%) participate in the formation of defect complexes. Carbon solubility in YAG is predicted to exhibit a pronounced minimum under moderately reducing conditions and to reach a maximum under either strongly reducing or oxidizing atmospheres. The formation of negatively charged CO defects in YAG grown under strongly reducing conditions significantly enhances the concentration of charged oxygen vacancies, leading to an increase of several orders of magnitude in their concentration.

LaCoO3 (LCO) undergoes a cubic to rhombohedral structural phase transition at ∼1600 K, a metal–insulator transition at ∼550 K, and a spin-state transition at ∼100 K. The thermodynamics of spin-state phase transitions for LCO have been studied using the 2-4-6 Landau–Ginzburg (LG) free energy functional (ΔG) developed in terms of mode amplitude of octahedral tilt (primary order parameter), symmetry-adapted strains, and pure electronic free energy (depicting gradual change of high-spin population fraction). The expansion coefficients of (ΔG) are determined using experimentally reported structural parameters and by employing first principle-based calculations. The spin crossover transition is predicted to be ∼75 K. The developed LG free energy functional model can successfully explain the temperature evolution of mode amplitude of primary order parameter (QR4+), symmetry-adapted strains ea (particularly characteristic hump ∼70 K) and e4, and population of high-spin state (n). The present study depicts the primary role played by octahedral tilt in the spin-state phase transition of LCO.

In biological systems, adaptive responses to environmental stimuli are facilitated by sensory transduction, where receptors transform stimuli into dynamic intermediate electrical signals for further processing. For bioinspired artificial systems, this suggests the need to develop concepts that transduce various stimuli into electrical intermediates for recognition. Inspired by biological magnetoreception in elasmobranchs, which sense magnetic environmental profiles for navigation, we introduce an artificial sensory transduction system for magnetic profile recognition of objects using electromagnetic induction to generate electrical intermediate signaling, coupled with machine learning for decoding. We design moldable magnetic soft composites (MSCs) comprising magnetic particles in a zwitterionic polymer matrix, encoding with both static (shape, rheology, and magnetization) and dynamic (magnetization decay) multidimensional features. Upon translocation through a receiving coil, MSCs generate distinct transient induced electrical signals. Machine learning algorithms decode the static and dynamic information with ∼100% and 87.5% recognition accuracy, respectively, with a recognition strength of 3 bits and a large information-carrying capacity of 10⁶²-10⁹³⁴ possible encoded states. We suggest that electromagnetic induction in soft composites is a useful and generalizable concept for sensory transduction in emerging adaptive dissipative bioinspired materials, haptic systems, and soft robotics.

The spatial heterogeneity of pathological factors in diabetic chronic wounds (DCWs) limits the development of effective treatment strategies. Here, a hydrogel-based wound dressing integrated with a dissolving microneedle array (H@MN) that orchestrates a novel spatiotemporal cascade reaction strategy is presented. Compared to the classical temporal cascade reaction, the spatiotemporal cascade reaction is characterized by spatially compartmentalized catalysts, which rely on the cross-regional diffusion of initial reaction products to the subsequent catalyst site to drive the sequential catalytic processes. Targeting the pathological features of DCWs, the glucose oxidase (GOX)-, superoxide dismutase (SOD)-, and catalase (CAT)-catalytic reactions are selected, which are catalyzed by natural enzymes or nanozymes. By integrating these catalysts into a spatiotemporal cascade reaction within the H@MN, it can intervene in and dynamically modulate the pathological factors in different spatial domains of DCWs at various temporal stages. Both in vitro and in vivo experiments confirm that the H@MN-enabled spatiotemporal cascade reaction, when combined with photothermal therapy, achieves superior healing efficacy in DCWs. The H@MN-enabled spatiotemporal cascade reaction is believed to inspire a generalizable strategy for treating diverse diseases characterized by spatially varied pathological microenvironments, offering a promising paradigm for advanced therapeutics.

Perovskite thin film-based laser diodes have emerged as promising candidates for on-chip laser sources. However, despite the successful demonstration of optically pumped lasing, the realization of electrically pumped perovskite laser has proved to be quite challenging. Here, we investigated the optical gain mechanism in polycrystalline perovskite thin film by mapping the spatial distributions of amplified spontaneous emission within the heterogeneous thin film and its spatial correlation with the local electronic properties. We discovered that optical gain within these polycrystalline perovskite thin films occurs primarily at defective sites, where despite the low photoluminescence efficiency demonstrated high optical gain efficiency, lower treshold and long photocarrier lifetime. Our findings highlight the importance of defects in the development of electrically pumped laser diodes.

The development of all-solid-state lithium metal batteries (ASSLMBs) has pushed beyond the energy density limit of conventional liquid systems. However, stress concentration remains a critical yet poorly understood cause of degradation in ASSLMBs, particularly in widely used polycrystalline (PC) Ni-rich cathode systems. Herein, we design cavity-contained PC LiNi_0.9Co_0.05Mn_0.05O₂ (NCM) cathode particles to resolve the stress concentration problem in particle-electrode-battery multiscale by bottom-up stress management. Synchrotron x-ray tomography and multiscale finite element simulations disclose the cathode reaction heterogeneity initiates stress concentration and particle-electrode-battery multiscale mechanical-electrochemical degradation. Compared to cavity-free and multi-cavity NCM, central-cavity NCM suppressed cracking within the particles through shortened ionic transport distances and a built-in stress-relief space, enhanced (de)lithiation depth and uniformity at the cathode, reduced porosity and fracture in the electrolyte, and inhibited lithium dendrite formation at the anode, suggesting significantly improved stress uniformity in particle-electrode-battery levels. Consequently, ASSLMBs using the central-cavity NCM deliver a superior cycling stability (86.4% after 200 cycles and 81.5% after 400 cycles), outperforming both the traditional cavity-free NCM (51.6% after 200 cycles) and highly anticipated single crystal NCM (44.2% after 400 cycles). This work links particle-electrode-battery multiscale mechanical-electrochemical behavior, providing valuable insights for designing ASSLMBs with long lifespan from a holistic perspective.

Next generation technologies linking living systems to computers will require materials built on biology, an approach that may address persistent challenges in stable and multimodal information exchange. Here, we present a semi-synthetic hydrogel, designed to emulate key features of native extracellular matrix (ECM) while offering electrically tunable functionality. We engineer interactions between sulfated glycosaminoglycans (sGAGs) and a semiconducting organic polymer (poly(3,4-ethylenedioxythiophene), PEDOT) within a soft hydrogel network (PEDOT:sGAGh). We demonstrate control over the material's nanoarchitecture, electrochemical behavior, and biomolecular interactions. In particular, PEDOT:sGAGh exhibits affinity for bioactive proteins, including growth factors, and allows their release or retention to be modulated by low-voltage stimulation. This enables electrical control over macromolecular cues for cell differentiation, a capability not found in natural ECM or conventional conductive hydrogels. These functions are achieved with ultra-low PEDOT content (≈1 wt.%), preserving the hydrogel's tissue-like softness and high water content. The PEDOT:sGAGh material can be integrated as a bioactive coating on electrodes, or into 3D organic electrochemical transistors (OECTs). Our results position PEDOT:sGAGh as a versatile platform for realizing biohybrid circuits that bridge molecular signaling and solid-state electronics, thus paving the way for brain-machine interfaces that operate beyond purely electrical modes of interaction.

Room-temperature sodium─sulfur (RT Na─S) batteries face sluggish redox kinetics and severe polysulfide shuttling. Here, a quasi-solid-state redox pathway is activated via an unsaturated coordination chemistry strategy, in which unsaturated MoS₂ anchored on cross-linked carbon microspheres forms a multifunctional sulfur host (S@U-MoS₂/C) that combines strong polysulfide adsorption with accelerated redox kinetics. Structural and electronic analyses show unsaturated Mo sites act as Lewis acid centers for rapid, selective polysulfide conversion. In situ transmission electron microscopy with newly developed Na-ion diffusion descriptors visualize ultrafast nanoscale sodiation dynamics and quantify Na-ion transport. Consequently, the S@U-MoS₂/C cathode delivers an impressive capacity of 933 mAh g^- ¹ after 150 cycles at 200 mA g^- ¹ and retains 425 mAh g^- ¹ after 30 000 cycles at 10 A g^- ¹. This work provides a mechanistic blueprint for designing high-rate, long-life Na─S batteries by coupling catalysis with structural confinement.

Operating stability is a critical challenge for all-perovskite tandem solar cells, with the degradation of wide-bandgap (WBG) perovskite films under high humidity posing a major obstacle to their commercial application. Herein, we demonstrate an internal encapsulation strategy in which the phosphonic acid-terminated hydrophobic [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid molecules act not only as a buried hole-transporting layer in our devices, but also anchor to hydroxyl groups on the surface of the atomic layer deposition-grown tin oxide electron transport layer, forming an ultrathin and hydrophobic capping layer. This layer protects WBG perovskites from humidity-induced degradation while maintaining efficient interfacial charge transport, thereby preserving high device efficiencies and markedly improving stability. Consequently, encapsulated WBG (1.77 eV) perovskite devices with a maximum power conversion efficiency (PCE) of 20.58% retained 95% of their initial PCEs after 2500 h of storage at 65% relative humidity and 2000 h at 85% relative humidity. Furthermore, under ISOS-L-1 conditions, the encapsulated WBG and all-perovskite tandem (with a maximum steady-state PCE of 29.01%) devices maintained 90% of their initial efficiencies after 2000 and 750 h of continuous operation under 1-sun illumination, respectively. This strategy effectively enhances moisture and operational stability, providing a viable path for the commercialization of high-performance all-perovskite tandems.

An ideal guided bone regeneration (GBR) membrane must simultaneously maintain structural rigidity and adhesive properties for early space stabilization, defense against bacteria, efficiently manage inflammation and thus promote periodontal regeneration. Herein, we engineer a novel microneedle-nanosheet (MN) composite membrane that enables conformal adhesion to bone surfaces and sequentially targets the bacterial and inflammatory phases in periodontitis (PD). Upon implantation, with the instant degradation of the polyvinyl alcohol (PVA) layer, MN achieves adaptive adhesion to periodontal defect sites via nanoscale properties. Accelerated degradation of gelatin methacryloyl (GelMA) layer enables sustained antimicrobial peptide release to control periodontal pathogens, while slow degradation of microneedle facilitates sustained delivery of mesenchymal stem cell-derived exosomes. In vitro, MN exhibits favorable mechanical stability, potent antibacterial activity against periodontal pathogens, biocompatibility, and promotes osteogenesis/angiogenesis. In rat and beagle dog periodontal bone defect models, MN enhances immunomodulation, osteogenesis, and angiogenesis, resulting in significant alveolar bone regeneration. 16S rRNA sequencing reveals reduced abundance of PD-associated bacterial communities, while RNA sequencing analysis further demonstrates activation of immune signaling pathways. In summary, MN adapts to critical demands for next-generation GBR membranes that offer a dynamic, bio-integrated microenvironment for tissue healing and regeneration by enabling temporally regulation, from space maintenance to multiplexed biological functions.

Water dissociation plays a central role in key electrocatalytic reactions-including hydrogen evolution, oxygen evolution, CO₂ reduction, and nitrogen reduction-by serving as the essential proton or hydroxyl source that fundamentally governs reaction pathways and product selectivity. However, its mechanism has long been oversimplified as an isolated chemical step occurring at a single active "dissociation" site, neglecting the profound influence of the interfacial microenvironment between catalyst and electrolyte. Recent advances reveal that water dissociation is dynamically coupled with, and actively reshapes, the interfacial microenvironment, thereby enabling performance breakthroughs across diverse reactions. This review systematically analyzes the multiscale mechanisms underlying this coupling, surveys advanced characterization techniques for probing dynamic interfaces, and discusses rational strategies-including catalyst engineering, molecular modification, and electrolyte design-for actively tuning the microenvironment to accelerate water dissociation and direct reaction pathways. This interfacial-system perspective offers a transformative framework for designing next-generation electrocatalysts, with broad implications for sustainable energy technologies such as water electrolyzers, fuel cells, and carbon/nitrogen reduction systems.

Inspired by the environment-adaptive behaviors of water striders, we 3D-printed a light-driven liquid crystal elastomer (LCE) swimming robot, OptiLCE Strider, capable of multimodal locomotion and adaptive reconfiguration at the air-water interface. Utilizing carbon nanotubes (CNTs) as photothermal fillers and dynamic disulfide bonds for shape reconfigurability, the robot exhibits three distinct propulsion modes: Marangoni-effect-driven continuous motion under low light intensity (1.3-7.2 mm s^- ¹), steam-wave-induced pulsatile locomotion under high light intensity (12.5-16.8 mm s^- ¹), and flapping propulsion enabled by reversible LCE deformation (4.6-6.9 mm s^- ¹). The dynamic disulfide bonds enable exceptional structural reconfigurability and environmental adaptability for the LCE robot to execute complex tasks, including maze navigation, cargo capture/transport, programmable rotation, and light-powered jumping (escape from grounded or obstructed states via actuation energy storage/release, with jumping height/distance 6×/3.3× the robot length). The qualitative phase map guides locomotion mode selection, while energetic cost analysis reveals a clear force-efficiency trade off among the three modes, guiding application specific selection. This study highlights the potential of dynamic LCE-based robots for intelligent systems in liquid interface environments, paving the way for versatile applications in soft robotics and biomimetic engineering.

Bone mineral forms both inside and between collagen fibrils in the extracellular matrix. While the morphology of intrafibrillar bone mineral has been hypothesized to be primarily controlled by the size and shape of the restricted spaces inside collagen fibrils within which the mineral forms, what controls the architecture of the extrafibrillar mineral is still an open question. While bone mineral is primarily apatitic in composition, it also contains significant quantities of cell respiration metabolites, in particular, carbonate, citrate, and lactate. An as-yet unanswered question is what, if any, role do these metabolites collectively play in determining the 3D architecture of bone mineral. Here, we propose a composite model of bone mineral that accounts for both intra- and extrafibrillar mineral environments, and to that end, we develop apatitic materials containing citrate and lactate or carbonate that mimic the densely packed ionic environments within which bone mineral forms in vivo. We find that incorporating citrate and lactate leads to complex mineral architectures reminiscent of those in extrafibrillar bone mineral, including mineral crystal curvature. Our results suggest that metabolic acids may play an important role in building the 3D architecture of extrafibrillar bone mineral.

Despite significant advances in nonlinear optical (NLO) materials, a systematic strategy for designing mid-infrared (mid-IR) NLO oxides that simultaneously exhibit strong second-harmonic generation (SHG) efficiency and wide optical transparency remains elusive. Herein, we report two polar antiperovskite oxide materials, (Pb1.5Cd1.5)GeO5 (PCGO) and Pb3GeO5 (PGO). Structural analyses reveal that PCGO adopts a 2H-hexagonal antiperovskite structure, whereas PGO features a three-dimensional antiperovskite framework. Both materials are thermally stable up to approximately 900 °C and exhibit wide optical transparency extending into the mid-IR region (0.3–13 μm). Powder SHG measurements indicate that PCGO and PGO exhibit strong SHG efficiencies of 0.5 and 1.3 times that of AgGaS2, respectively, along with particle-size-dependent SHG responses indicative of phase-matching behavior. Further first-principles calculations reveal moderate birefringence values of 0.053 and 0.058 at 1064 nm for PCGO and PGO, respectively, corresponding to shortest phase-matching (PM) wavelengths of 737 and 776 nm. A closer structural investigation and density functional theory calculations suggest that the pronounced distortions of OPb/Cd6 and OPb6 octahedra, together with highly polarizable cations, play a dominant role in governing the SHG responses. These results highlight polar antiperovskite oxides as a promising platform for the development of next-generation mid-IR NLO materials.

Antibiotic combination in time and space is a key strategy to combat antimicrobial resistance. The success of such treatment designs requires their robust efficacy across treatment conditions and a pathogen's genomic diversity. This study found that an initial treatment with a β-lactam antibiotic causes robust cellular sensitization towards an aminoglycoside antibiotic across the high-risk human pathogen Pseudomonas aeruginosa, including resistant strains. This phenomenon of cellular sensitization, termed negative hysteresis, is modulated by the Cpx envelope stress response system and linked to membrane stress during growth. The increase in efficacy is achieved through a β-lactam induced elevated cellular uptake of the subsequently administered aminoglycoside. Negative hysteresis and the Cpx system are linked in several cases to the expression of synergistic drug interactions, thus enhancing efficacy of antibiotic combinations. Overall, our study identifies the phenomenon of negative hysteresis as a robustly inducible phenotype and thus a unique focus for optimizing antimicrobial therapy.

Phase-separated biomolecular condensates are functional elements in cells, contribute to protocell formation in prebiotic systems, and represent a distinct class of soft matter. Controlling condensate mechanochemistry is critical for function and material properties. Although photochemical processes are widespread in nature and can be harnessed in engineering, it remains unclear how condensate formation affects photochemistry, and conversely how photochemistry alters condensate dynamics. Using scanning probe microscopy combined with UV-controlled photochemistry and optical imaging, we develop assays to probe mechanical transitions and fusion dynamics in condensate droplets, revealing that UV-induced thymine dimerization alters condensate nucleation and coalescence. Depending on the frequency and topological arrangement of thymine dimers, particularly the balance between inter- and intrachain crosslinks, UV can drive transitions from liquid-like to solid-like states or induce aggregates. UV also promotes arrested fusion and stable compartmentalization of droplets, resilient to environmental changes and with implications for prebiotic chemistry and bio-inspired engineering.

Thermal expansion is an intrinsic property of metals and alloys, posing a critical challenge for achieving dimensional stability in lightweight systems where low atomic mass enhances lattice vibrations. Here, we present a strain recovery compensation strategy that achieves three orders of magnitude reduction in thermally induced volume change, enabling zero thermal expansion (ZTE) in a rare-earth magnesium alloy containing 1.2 vol.% Al-stabilized MnCoGe particles. The coefficient of thermal expansion is reduced from 28 × 10⁻⁶ °C⁻¹ to 0.02 × 10⁻⁶ °C⁻¹ over 25-150 °C-the highest thermal stability reported for any alloy. This alloy also retains high compressive strength (424 MPa), ductility (12%), and ultralow density (1.93 g/cm³). The ZTE behavior arises from sustained compressive strain, maintained by reversible martensitic transformation of the embedded particles. Beyond realizing a dimensional stable lightweight alloy, this work establishes a generalizable principle for achieving thermal dimensional stability in metals via recoverable strain.