Linglong Li

Electron acceptors such as tetracyanoquinodimethane (TCNQ) and its fluorinated analogue F4TCNQ are foundational to charge-transfer and doping chemistry. At interfaces formed by deposition of these acceptors onto donor substrates, reduced anionic species can naturally coexist with unreacted neutral acceptors, creating mixed-valence environments beyond conventional one-way charge transfer. Here, we report charge-resonance polymerization of acceptors at donor–acceptor interfaces. Deposition of neutral acceptors onto electron-donor substrates partially reduces the acceptors to anion salts, establishing neutral/radical-anion contact. This mixed-valence interface enables cyclic neutral–anion charge-resonance interactions that initiate a self-propagating polymerization process. This dynamic process operates across diverse donor substrates and from room temperature to 250 °C, producing large-area membranes up to 30 × 30 cm with persistent radicals and room-temperature magnetic hysteresis. These findings establish intraspecies charge resonance as a design principle for self-activating polymerization and offer fresh insight into charge behavior at donor–acceptor interfaces.

The development of active nanophotonics demands configurable materials with high spatial resolution. Here, we demonstrate the direct fabrication of a flat optical diffraction grating utilizing a lithography-free, probe-based nanoscale patterning strategy. Specifically, local hydrogen ion injection via a Pt-coated atomic force microscopic probe triggers a seven-order-of-magnitude resistivity rise and a 12.6% out-of-plane lattice expansion in NdNiO3 film, dynamically transforming the nano- or microscale area from an opaque metal into a transparent insulator. Alongside this extremely different optical contrast, the tip-induced process features a deep subwavelength spatial resolution of ∼100 nm, with a low operational threshold voltage of ∼1.1 V, and continuous grayscale programmability. By leveraging this distinct optical contrast and high spatial fidelity, we successfully fabricate and optically validate a microdiffraction grating and holographic diffraction. This work establishes atomic-probe-controlled hydrogen injection as a powerful, energy-efficient paradigm for prototyping programmable diffractive optical elements and next-generation flat optics.

Materials with room-temperature magnetic ordering and switchable polarization are essential for spintronic devices. Although 3 d transition metal oxides exhibit potential, their Curie temperature (T_C) remains unsatisfactory, and coexistence of magnetic and polar order has not been realized in 4 d/5 d oxides. Here, through epitaxial strain and 3d-4d cation ordering engineering, a ferrimagnetic insulating state (T_C ~ 623 K) is achieved in La₂CoRuO₆ films, coexisting with switchable short-range polar nanodomains. Atomic-scale investigations and density functional theory calculations reveal that compressive strain enhances lattice distortions. These distortions, combined with high-spin state of Co²⁺ ions and ordered B-site cations, significantly enhance Co-O-Ru antiferromagnetic superexchange, inducing the ferrimagnetic insulating state. Concurrently, the gradient BO₆ octahedral rotations with inhomogeneous evolution trigger B-site ions' displacements, driving the formation of polar nanodomains. Our work fills the experimental gap in realizing magnetic and polar order coexistence in 4 d/5 d oxides and opens new avenues for designing high-T_C multiferroics.

Rolling two-dimensional materials into one-dimensional nanoscrolls introduces curvature, chirality and symmetry breaking, enabling emergent properties. Conventional methods relying on external driving forces, however, exhibit poor control, low yield and limited reproducibility. Here we report spontaneous scrolling in polar van der Waals materials via an electrochemical intercalation/exfoliation process, enabling scalable nanoscroll production. This self-rolling is driven intrinsically by out-of-plane electric polarization (P_⊥), where the magnitude of P_⊥ is modulated by the intercalant size. Validated across eight polar materials, this approach achieves virtually 100% yield and reproducibility with defined scrolling direction, surpassing external driving force limitations. The nanoscrolls exhibit layer-independent inversion symmetry breaking and coherently enhanced second-harmonic generation, exceeding two-dimensional flakes by ~100-fold and rivalling leading two-dimensional nonlinear materials. Electrochemical initiation further facilitates metal-ion co-intercalation, yielding ten hybrid nanoscroll architectures. These findings establish a scalable route to create one-dimensional nanostructures and hybrid heterostructures, paving the way for designer quantum solids and van der Waals superlattices in quantum nanodevices.

Ferroelectric oxides are generally prone to brittle deformation, which impedes their applicability in flexible devices. Using a damage-free peel-off process, we successfully synthesized wrinkled 10 nm thick membranes of zirconium-doped hafnium oxide Hf_0.5Zr_0.5O₂ (HZO). We studied their self-restoration dynamics via in situ scanning probe microscopy. Substantial deformations were induced as the tip descended by applying and sustaining a predefined static force at the crest of the wrinkled membrane. The membrane was fully restored to its original wrinkled state within a specific force range, with no observed damage after force removal. The membrane demonstrated self-restoration even after forces exceeding 100 nN, which completely collapsed the wrinkles, highlighting the exceptional flexibility of these freestanding HZO membranes─an uncommon property among functional oxides. Combining phase-field simulations, we observed the emergence of a region exhibiting continuous variation in polarization intensity within the strained area. The formation of this specific domain structure plays a pivotal role in the self-restoration behavior of the freestanding ferroelectric membranes. This self-restoration capability is essential for the long-term stability of flexible electronic devices, such as sensors, energy harvesters, and electronic skins.

Magnetoelectricity coupling is realized in the van der Waals CuCrP ₂ S ₆ system by doping.

The authors want to make the corrections to the paper, and confirm that the scientific conclusions are unaffected. The original publication has also been updated.

Ferroelectricity-based storage technology is anticipated to achieve nonvolatile, low-power, and high-density storage in integrated field circuits. Here, the phenomena of electrically reversible switching of nanocracks in the tellurium film/ferroelectric PMN-PT heterojunctions are discussed. Upon the application of external electric fields (±2 kV/cm), the nonvolatile resistance on-off ratio reached over 106 at room temperature. This was achieved through the opening and closing of cracks in the Te film caused by the electric-field-driven flipping of 109° ferroelectric domains in a ferroelectric single crystal. In addition, the ON/OFF resistance states remain stable even after more than 103 cycles and the retention time exceeds 6 h, demonstrating excellent fatigue resistance performance of the device. This work renders a window to design nonvolatile memory by constructing electric-field tunable nanocracks in a semiconductor film/ferroelectrics heterojunction system.

Single crystals of (001)‐oriented 0.7Pb(Mg_1/3Nb_2/3)−0.3PbTiO₃ (PMN‐30PT) with a composition near the morphotropic phase boundary have attracted considerable attention due to their superior dielectric and electromechanical performance. Recently, a new alternating current (electric field) poling approach used for the enhancement of dielectric and piezoelectric properties. However, the microscopic domain variants that govern the performance, especially under high‐frequency alternating current (AC) voltages, remain largely unexplored. In this work, the domain microstructure under AC poling reveals the presence of four monoclinic (M_A) domain variants using a suite of scanning probe microscopy methods, and X‐ray diffraction (XRD) reciprocal space mapping is tuned. It is reported on the emergence of hierarchical fine domains – needle‐shaped, and 109° domain walls under applied high‐frequency AC poling. Time‐resolved Kelvin probe force microscopy (KPFM) reveals the charge dynamics and relaxation behavior of these needle domains and walls. The findings provide new insight and guidance to the domain engineering by high‐frequency AC poling for the development of advanced transducer technology.