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This paper investigates some synchronization behaviors of high‐dimensional Kuramoto models with nonidentical oscillators and interconnection digrphs. By using the matrix Riccati differential equation of the state error variables, it is proved that a high‐dimensional Kuramoto model can achieve local practical synchronization when the interconnection digraph is strongly connected or has a spanning tree. Compared with the existing practical synchronization literature, the results are based on general digraphs instead of complete graphs. Moreover, the complete synchronization is proved for proportional nonidentical oscillators limited on a half‐sphere and interconnected by a strongly connected digraph. Finally, some numerical simulations are given to validate the obtained theoretical results.

For bone defect repair under co-morbidity conditions, the use of biomaterials that can be non-invasively regulated is highly desirable to avoid further complications and to promote osteogenesis. However, it remains a formidable challenge in clinical applications to achieve efficient osteogenesis with stimuli-responsive materials. Here, we develop polarized CoFe 2 O 4 @BaTiO 3 /poly(vinylidene fluoridetrifluoroethylene) [P(VDF-TrFE)] core-shell particle-incorporated composite membranes with high magnetoelectric conversion efficiency for activating bone regeneration. An external magnetic field force conduct on the CoFe 2 O 4 core can increase charge density on the BaTiO 3 shell and strengthens the β-phase transition in the P(VDF-TrFE) matrix. This energy conversion increases the membrane surface potential, which hence activates osteogenesis. Skull defect experiments on male rats showed that repeated magnetic field applications on the membranes enhanced bone defect repair, even when osteogenesis repression is elicited by dexamethasone or lipopolysaccharide-induced inflammation. This study provides a strategy of utilizing stimuli-responsive magnetoelectric membranes to efficiently activate osteogenesis in situ. Biomaterials that can be non-invasively activated to promote bone growth would be useful tools to repair bone defects in patients with comorbidities like inflammation or impaired osteogenesis. Here, the authors develop a composite membrane that can be stimulated by an external magnetic field and use it to correct skull defects in rats treated to reflect such comorbidities.

Charged domain walls in ferroelectrics exhibit a quasi-two-dimensional conduction path coupled to the surrounding polarization. They have been proposed for use as non-volatile memory with non-destructive operation and ultralow energy consumption. Yet the evolution of domain walls during polarization switching makes it challenging to control their location and conductance precisely, a prerequisite for controlled read–write schemes and for integration in scalable memory devices. Here, we explore and reversibly switch the polarization of square BiFeO3 nanoislands in a self-assembled array. Each island confines cross-shaped, charged domain walls in a centre-type domain. Electrostatic and geometric boundary conditions induce two stable domain configurations: centre-convergent and centre-divergent. We switch the polarization deterministically back and forth between these two states, which alters the domain wall conductance by three orders of magnitude, while the position of the domain wall remains static because of its confinement within the BiFeO3 islands.

Multichannel meta-imaging, inspired by the parallel-processing capability of neuromorphic computing, offers considerable advancements in resolution enhancement and edge discrimination in imaging systems, extending even into the mid- to far-infrared spectrum. Currently typical multichannel infrared imaging systems consist of separating optical gratings or merging multi-cameras, which require complex circuit design and heavy power consumption, hindering the implementation of advanced human-eye-like imagers. Here, we present printable graphene plasmonic photodetector arrays driven by a ferroelectric superdomain for multichannel meta-infrared imaging with enhanced edge discrimination. The fabricated photodetectors exhibited multiple spectral responses with zero-bias operation by directly rescaling the ferroelectric superdomain instead of reconstructing the separated gratings. We also demonstrated enhanced and faster shape classification (98.1%) and edge detection (98.2%) using our multichannel infrared images compared with single-channel detectors. Our proof-of-concept photodetector arrays simplify multichannel infrared imaging systems and offer potential solutions in efficient edge detection in human-brain-type machine vision. Here, the authors report the realization of a multichannel mid-infrared imaging system based on zero-bias type-printed graphene plasmonic photodetector arrays on ferroelectric substrates, showing enhanced infrared image recognition and edge detection accuracy.

The electronic conductivities of ferroelectric domain walls have been extensively explored over the past decade for potential nanoelectronic applications. However, the realization of logic devices based on ferroelectric domain walls requires reliable and flexible control of the domain-wall configuration and conduction path. Here, we demonstrate electric-field-controlled stable and repeatable on-and-off switching of conductive domain walls within topologically confined vertex domains naturally formed in self-assembled ferroelectric nano-islands. Using a combination of piezoresponse force microscopy, conductive atomic force microscopy, and phase-field simulations, we show that on-off switching is accomplished through reversible transformations between charged and neutral domain walls via electric-field-controlled domain-wall reconfiguration. By analogy to logic processing, we propose programmable logic gates (such as NOT, OR, AND and their derivatives) and logic circuits (such as fan-out) based on reconfigurable conductive domain walls. Our work might provide a potentially viable platform for programmable all-electric logic based on a ferroelectric domain-wall network with low energy consumption. Ferroelectric domain walls have been extensively explored for nanoelectronics, but the logic devices are still challenging. Here, the authors propose programmable logic gates and circuits based on electric-field controllable conductive domain walls.

Ferroelectrics, which generate a switchable electric field across the solid–liquid interface, may provide a platform to control chemical reactions (physical properties) using physical fields (chemical stimuli). However, it is challenging to in-situ control such polarization-induced interfacial chemical structure and electric field. Here, we report that construction of chemical bonds at the surface of ferroelectric BiFeO 3 in aqueous solution leads to a reversible bulk polarization switching. Combining piezoresponse (electrostatic) force microscopy, X-ray photoelectron spectroscopy, scanning transmission electron microscopy, first-principles calculations and phase-field simulations, we discover that the reversible polarization switching is ascribed to the sufficient formation of polarization-selective chemical bonds at its surface, which decreases the interfacial chemical energy. Therefore, the bulk electrostatic energy can be effectively tuned by H + /OH − concentration. This water-induced ferroelectric switching allows us to construct large-scale type-printing of polarization using green energy and opens up new opportunities for sensing, high-efficient catalysis, and data storage. Controlling ferroelectric polarization is conventionally achieved by applying electric fields, mechanical force or similar. Here reversible switching of the bulk polarization of a BiFeO 3 thin film is demonstrated by pattering aqueous solution on to the surface enabling large-scale switching.

Spin waves may constitute key components of low-power spintronic devices. Antiferromagnetic-type spin waves are innately high-speed, stable and dual-polarized. So far, it has remained challenging to excite and manipulate antiferromagnetic-type propagating spin waves. Here, we investigate spin waves in periodic 100-nm-wide stripe domains with alternating upward and downward magnetization in La0.67Sr0.33MnO3 thin films. In addition to ordinary low-frequency modes, a high-frequency mode around 10 GHz is observed and propagates along the stripe domains with a spin-wave dispersion different from the low-frequency mode. Based on a theoretical model that considers two oppositely oriented coupled domains, this high-frequency mode is accounted for as an effective antiferromagnetic spin-wave mode. The spin waves exhibit group velocities of 2.6 km s−1 and propagate even at zero magnetic bias field. An electric current pulse with a density of only 105 A cm−2 can controllably modify the orientation of the stripe domains, which opens up perspectives for reconfigurable magnonic devices.Current pulses of 105 A cm−2 can control the orientation of 100-nm-wide stripe domains in La0.67Sr0.33MnO3 and spin waves of 10 GHz can propagate along these domains with a group velocity of 2.6 km s−1.

Solomon rings, upholding the symbol of wisdom with profound historical roots, were widely used as decorations in ancient architecture and clothing. However, it was only recently discovered that such topological structures can be formed by self-organization in biological/chemical molecules, liquid crystals, etc. Here, we report the observation of polar Solomon rings in a ferroelectric nanocrystal, which consist of two intertwined vortices and are mathematically equivalent to a 4 1 2 link in topology. By combining piezoresponse force microscopy observations and phase-field simulations, we demonstrate the reversible switching between polar Solomon rings and vertex textures by an electric field. The two types of topological polar textures exhibit distinct absorption of terahertz infrared waves, which can be exploited in infrared displays with a nanoscale resolution. Our study establishes, both experimentally and computationally, the existence and electrical manipulation of polar Solomon rings, a new form of topological polar structures that may provide a simple way for fast, robust, and high-resolution optoelectronic devices. Polar Solomon rings in a ferroelectric nanocrystal have been observed and electrically manipulated, which consist of two intertwined vortices and are mathematically equivalent to a 4 1 2 link in topology based on knots and links theory.

A central goal of electronics based on correlated materials or ‘Mottronics’ is the ability to switch between distinct collective states with a control voltage. Small changes in structure and charge density near a transition can tip the balance between competing phases, leading to dramatic changes in electronic and magnetic properties. In this work, we demonstrate that an electric field induced two-step ferroelastic switching pathway in (011) oriented 0.71Pb(Mg 1/3 Nb 2/3 )O 3 -0.29PbTiO 3 (PMN-PT) substrates can be used to tune the Verwey metal-insulator transition in epitaxial Fe 3 O 4 films in a stable and reversible manner. We also observe robust non-volatile resistance switching in Fe 3 O 4 up to room temperature, driven by ferroelastic strain. These results provides a framework for realizing non-volatile and reversible tuning of order parameters coupled to lattice-strain in epitaxial oxide heterostructures over a broad range of temperatures, with potential device applications.

We have studied the magnetic and electrical transport properties of epitaxial NiAs-type CrTe thin films grown on SrTiO 3 (111) substrates. Unlike rectangle hysteresis loops obtained from magnetic measurements, we have identified intriguing extra bump/dip features from anomalous Hall experiments on the films with thicknesses less than 12 nm. This observed Hall anomaly is phenomenologically consistent with the occurrence of a topological Hall effect(THE) in chiral magnets with a skyrmion phase. Furthermore, the THE contribution can be tuned by the film thickness, showing the key contribution of asymmetric interfaces in stabilizing Néel-type skyrmions. Our work demonstrates that a CrTe thin film on SrTiO 3 (111) substrates is a good material candidate for studying real-space topological transport.