Ruifen Dou

Transition metal dichalcogenide (TMD) lateral heterostructures provide unique platforms to study nanoscale physics, but progress is limited by the difficulty of producing high‐quality interfaces, which require atomic‐precision growth rather than simple stacking. We report a controllable two‐step chemical vapor deposition (CVD) process for directed epitaxy growth of MoS ₂ /WS ₂ monolayer lateral heterostructures. Atom‐resolution scanning tunneling microscopy measurements demonstrate an atomically sharp, defect‐free MoS ₂ /WS ₂ interface formed along the sulfur zigzag edge of MoS ₂ , indicating an atomic‐substitution‐nucleation growth mechanism. Domain sizes of both MoS ₂ and WS ₂ can be precisely tuned from several to hundreds of micrometers. The zig‐zag interface creates an intermediate energy level at the junction, prolonging photogenerated carrier recombination lifetimes, in agreement with theoretical band‐structure calculations. This work establishes a scalable synthesis route to high‐quality TMDs lateral heterostructures with an atomic‐scale shape interface and tunable domain sizes, accelerating the applications in electronic and optoelectronic devices.

Precisely constructing transition metal (TM) active sites in two-dimensional materials can enhance water-splitting, whereas the role of geometric factors such as interfacial curvature remain poorly understood. Nanotube (NT) provides a well-defined curved architecture that can modulate electron interactions and reactivity. Here, we rationally design a series of TM@g-C6N6 NTs and use first-principles calculations assisted by machine learning to elucidate how dimensional reduction and curvature govern water-splitting activity. We find that reduced curvature radius systematically promotes water splitting. Notably, the Ir- and Rh-decorated g-C6N6 NTs show remarkable electrocatalytic performance with calculated overpotentials of 0.05 eV for the hydrogen evolution reaction and 0.20 eV for the oxygen evolution reaction. Curvature-induced confinement drives reconstruction and reoccupation of the d-orbitals states near the Fermi level upon transitioning from a flat plane to a tubular geometry. More importantly, for different reaction intermediates, we identify a curvature-dependent inversion of the dominant adsorption orbital transition from the dz2 to the dx2-y2 , which directly correlates with enhanced catalytic activity. Our results establish interfacial curvature as a key manipulator for tuning electronic structure and water-splitting reactivity in TM@g-C6N6 NT single-atom catalysts and provide a new perspective on modulating electronic and catalytic properties in TM@g-C6N6 NT-like structures.

Twisted trilayer (Tt) transition metal dichalcogenides with multiple rotational degrees of freedom offer unprecedented opportunities for constructing large‐wavelength moiré superlattices to maximize the effect of correlated behaviors. Precisely stacking trilayer structures to realize ultra‐large moiré superlattices remains a significant challenge, hindering investigations of moiré‐tuned excitonic properties. Here we fabricate Tt MoS ₂ via chemical vapor deposition, in which two commensurate twists of 2.7° and 21.9° are sequentially introduced from the top to middle, and to bottom layers. An unprecedented super‐moiré structure with an ultra‐large periodicity of around 24 nm is achieved, 30 times larger than that of 21.9°‐bilayer MoS ₂ , hierarchically composed of periodical mirror‐symmetric triangular tessellation patterns consisting of five kinds of high‐symmetric stacking registrations and the relaxation regions resulting from the interlayer gliding. This robust ultra‐large‐period superstructure generates a deep moiré potential to effectively suppress intralayer moiré excitons recombination and be against intervalley exchange interaction at the magnetic field up to 9T, associated with the enhanced layer‐valley‐locked polarization by two‐fold larger than that of the trilayer systems with incommensurate angles. Our work presents angle‐dependent super‐moiré architectures in Tt systems as a versatile platform for designing moiré quantum materials with tailored optoelectronic responses, advancing applications in valleytronic and excitonic devices.

Deterministic control of perpendicular magnetization via spin–orbit torque (SOT) offers a promising route toward nonvolatile, ultrafast, and energy-efficient spintronic applications. Obtaining large-scale, high-quality spin source materials with high charge-to-spin conversion efficiency remains challenging. Here, we fabricated large-area amorphous PtTe thin films using magnetron sputtering and investigated their SOT efficiency through spin-torque ferromagnetic resonance and current-induced magnetization switching measurements. The amorphous PtTe films exhibit a high SOT efficiency of 0.322 and a spin Hall conductivity comparable to that of crystalline PtTe2, which may originate from short-range ordered structures in amorphous PtTe films and increased scattering. This work paves the way for the large-area production and practical application of amorphous thin films as efficient spin sources in next-generation spintronic technologies.

The moiré superlattices have garnered significant attention due to their unique twist‐angle‐dependent electronic and optical properties. Creating high‐quality twisted bilayer structures stands as one of the major frontiers in the study of correlated moiré physical properties, however, which remains a challenge. Here, a cyclical‐carrier‐gas chemical vapor deposition method is employed to grow high‐quality twisted bilayers MoS ₂ . Stacking configurations and the growth mechanism of twisted bilayer MoS ₂ are systematically investigated, revealing that the relative rotation angle between the two layers is guided by the tilt grain boundaries (GBs) of the bottom layer. This relationship is elucidated through real‐time monitoring of the formation process of the top layer from nucleation to coalescence. Meanwhile, the interlayer exciton (X ^I ) strongly couples to the twist angle, and the enhanced intensity of X ^I peaks in TB‐MoS ₂ at specific twist angles of ≈22° and 38° is evidenced by low‐temperature (10K) photoluminescence and second harmonic generation spectra, which can be ascribed to the X ^I localization in the periodical moiré superlattice. The findings provide a viable method for the in‐ situ preparation of layered twisted materials guided by tilt GBs, which facilitates the exploration of novel optical and excitonic physics in moiré systems.

Transition metal selenides have attracted much attention in the field of energy storage materials due to their high theoretical capacity and suitable working potential. However, they still suffer from slow reaction kinetics and poor stability during cycling. The construction of heterostructures is an effective strategy to improve the electrochemical performance of materials, which can improve the diffusion kinetics of ions and enhance the conductivity and structural stability of electrodes. In this paper, an in situ self-assembly strategy is proposed to encapsulate VO(acac)₂ in a customized cavity of ZIF-8 to achieve uniform dispersion of vanadium species and then to obtain ZnSe/VSe₂@NC heterostructured materials with abundant heterointerface. Based on the experimental characterization combined with density-functional theory calculations, a strong built-in electric field is induced at the interface due to the large energy band structure difference between VSe₂ and ZnSe, which promotes charge-electron transfer and achieves fast electrochemical kinetics and satisfactory reversible capacity. As an anode material for sodium-ion batteries (SIBs), ZnSe/VSe₂@NC exhibits excellent multiplicity performance (254.46 mA h g^-1 at 10 A g^-1) and long cycle stability (317.52 mA h g^-1 after 2000 cycles at 5 A g^-1). This study provides an effective strategy for the rational design of anode materials for high-performance SIBs.

The Pt/Co/MgO/Cr multilayers were prepared by the molecular beam epitaxy (MBE) method, and the current-induced spin-orbit torque (SOT) in the epitaxial (111)-oriented Pt sample was characterized by Hall voltage harmonic measurements. The spin torque efficiency (ξSOT) was characterized, and the obtained ξSOT is 0.052. The SOT-driven complete magnetization reversal with the assistance of an in-plane external magnetic field was demonstrated by electrical measurements. The magneto-optic Kerr effect (MOKE) microscope measurement indicates that the magnetization reversal is accomplished by magnetic domain nucleation and domain wall motion. These results further help us to understand the SOT switching in the epitaxial Pt-based magnetic heterostructure and may facilitate its applications in spintronic devices.

The rational design of heterojunctions by coupling two or more two-dimensional (2D) materials is regarded as a feasible strategy to efficiently enhance photocatalytic-hydrogen performance by capturing solar energy to address the increasing global energy crisis. In this work, a functional MoS₂/ZnO heterojunction is proposed based on first-principles simulation. Our results reveal that the photogenerated electrons and holes in the MoS₂/ZnO heterojunction follow a specific Z-scheme pathway, highly facilitating redox reactions and optimizing optical properties in the visible-light region. Under external strain, the MoS₂/ZnO heterojunction demonstrates improved HER performance and remarkable optical-harvesting capabilities. Interestingly, the HER free energy for the heterojunction is only -0.04 eV under -5% compressive strain, highlighting its promising potential for photocatalytic hydrogen production. We observe that the absorption edge of the spectrum shifts gradually to the infrared region with increasing tensile biaxial strains, whereas compressive biaxial strains result in a blue-shift absorption spectrum. Additionally, all heterojunctions achieve excellent solar-to-hydrogen (STH) efficiencies exceeding 10%, demonstrating their capability to store sufficient solar energy. Our work offers a novel strategy for exploring highly efficient photocatalysts in the field of hydrogen energy with the ability to modulate their activity through external strain.