Layered magnetic systems with interlayer antiferromagnetic coupling are emerging as a promising platform for energy-efficient spintronic technologies, particularly in the form of van der Waals (vdW) magnets. The direct observation and manipulation of topological spin textures in perpendicularly magnetized 2D antiferromagnets, however, remain highly challenging due to their compensated magnetic states and rigid interlayer exchange, thereby hindering direct insight into spin ordering and functional exploration. Here, using spin-polarized low-energy electron microscopy, we directly visualize antiferromagnetic domains and emergent topological textures in the vdW antiferromagnet (Fe1-xCox)3GaTe2. We uncover tuneable stripe-like domain configurations that can be reconfigured into antiferromagnetic skyrmions under external stimuli, despite the absence of remanent magnetization. These results provide direct insight into spin ordering in a perpendicularly magnetized layered two-dimensional antiferromagnet and open new avenues for next-generation antiferromagnetic spintronic devices.

Graphene enables precise carrier-density control via gating, making it an ideal platform for studying electronic interactions. However, sample inhomogeneities often limit access to the low-density regimes where these interactions dominate. Enhancing carrier mobility is therefore crucial for exploring fundamental properties and developing device applications. Here, we demonstrate a significant reduction in external inhomogeneity using a double-layer graphene architecture separated by an ultra-thin hexagonal boron nitride layer. Mutual screening between the layers reduces scattering from random Coulomb potentials, resulting in a quantum mobility exceeding 1 0 7 c m 2 V - 1 s - 1 . Shubnikov-de Haas oscillations emerge at magnetic fields below 1 mT, while integer quantum Hall features are observed at 0.002 T. Furthermore, we identify a fractional quantum Hall plateau at a filling factor of v tot = - 10 / 3 at 2 T. These results demonstrate the platform's suitability for investigating strongly correlated electronic phases in graphene-based heterostructures.

Engineering proximity effects in twisted van der Waals heterostructures offers a powerful platform for designing electronic properties. While theoretical predictions of quantum interference in transition metal dichalcogenide-encapsulated graphene can selectively control the spin-orbit coupling component, experimental realizations have remained elusive. Here, we report pure valley-Zeeman spin-orbit coupling in monolayer graphene, achieved by encapsulation between two parallel twisted WSe_2 monolayers. We observed a symmetry-enforced reordering of Landau levels, which is driven by the competition between the fixed valley-Zeeman energy and the magnetic-field-dependent cyclotron energy. This reordering is characterized by a transition from symmetry-broken states in the quantum Hall effect to a restored fourfold degeneracy with integer or half-integer quantum Hall sequences. We also demonstrate the ability to completely quench the proximity spin-orbit coupling by tuning the encapsulated geometry.

Graphene enables precise carrier-density control via gating, making it an ideal platform for studying electronic interactions. However, sample inhomogeneities often limit access to the low-density regimes where these interactions dominate. Enhancing carrier mobility is therefore crucial for exploring fundamental properties and developing device applications. Here, we demonstrate a significant reduction in external inhomogeneity using a double-layer graphene architecture separated by an ultra-thin hexagonal boron nitride layer. Mutual screening between the layers reduces scattering from random Coulomb potentials, resulting in a quantum mobility exceeding. Shubnikov de-Haas oscillations emerge at magnetic fields below 1 mT, while integer quantum Hall features are observed at 0.002T. Furthermore, we identify a fractional quantum Hall plateau at a filling factor of at 2T. These results demonstrate the platform's suitability for investigating strongly correlated electronic phases in graphene-based heterostructures.

The coupling of ferroelectricity and magnetic order provides rich tunability for engineering material properties and demonstrates great potential for uncovering novel quantum phenomena and multifunctional devices. Here, we report interfacial ferroelectricity in moiré superlattices constructed from graphene and hexagonal boron nitride. We observe ferroelectric polarization in an across-layer moiré superlattice with an intercalated layer, demonstrating a remnant polarization comparable to its non-intercalated counterpart. Remarkably, we reveal a magnetic-field enhancement of ferroelectric polarization that persists up to room temperature, showcasing an unconventional amplification of ferroelectricity in materials lacking magnetic elements. This phenomenon, consistent across devices with varying layer configurations, arises purely from electronic rather than ionic contributions. Furthermore, the ferroelectric polarization in turn modulates quantum transport characteristics, suppressing Shubnikov-de Haas oscillations and altering quantum Hall states in polarized phases. This interplay between ferroelectricity and magneto-transport in non-magnetic materials is crucial for exploring magnetoelectric effects and advancing two-dimensional memory and logic applications.

Introducing topologically protected skyrmions in graphene holds significant importance for developing high-speed, low-energy spintronic devices. Here, we present a centrosymmetric ferromagnetic graphene/trilayer Cr2Ge2Te6/graphene heterostructure, demonstrating the anomalous and topological Hall effect due to the magnetic proximity effect. Through gate voltage control, we effectively tune the emergence and size of skyrmions. Micromagnetic simulations reveal the formation of skyrmions and antiskyrmions, which respond differently to external magnetic fields, leading to oscillations in the topological Hall signal. Our findings provide a novel pathway for the formation and manipulation of skyrmions in centrosymmetric two-dimensional magnetic systems, offering significant insights for developing topological spintronics.

The discovery of two-dimensional magnetic materials has provided an ideal platform for exploring physical phenomena in the two-dimensional limit. However, intrinsic two-dimensional antiferromagnetic materials have been rarely reported, limiting systematic studies of their electronic properties. The discovery of novel intrinsic two-dimensional antiferromagnets and the development of robust synthesis strategies, therefore, remain significant challenges. Here, we report the chemical vapor deposition synthesis of CrOCl monolayer films and nanosheets that exhibit excellent air stability. The CrOCl morphology is tunable, ranging from two-dimensional nanosheets to three-dimensional flower-like structures, with lateral sizes ranging from several microns to continuous monolayer films. Structural characterization confirms the material’s composition and high crystalline quality. Furthermore, magnetic measurements, supported by theoretical calculations, reveal a Néel temperature for CrOCl of ≈ 14 K. This work provides a reliable route for preparing two-dimensional antiferromagnetic materials. The development of novel two-dimensional antiferromagnets is crucial for enhancing the performance of spintronic devices. Here, authors realize the synthesis of CrOCl monolayer films and nanosheets that exhibit excellent performance.

alpha-RuCl3 is known for its potential to realize a Kitaev quantum spin liquid by tuning the competing interactions, such as doping effects. Here, we investigated the doping effect of alpha-RuCl3/graphene heterostructures and observed a G peak splitting related to different spins, as revealed by Raman spectroscopy. The deliberate disruption of the heterostructure led to a transition from a double G peak to a single peak, underscoring the significance of interface quality. This finding was corroborated by density functional theory calculations. Additionally, we distinguished the contributions of doping and strain by employing Raman mapping, drawing comparisons to CrCl3/graphene heterostructures. These findings present a high-resolution technique for assessing the uniformity of similar heterostructure surfaces and investigating the behavior of distinct spins in Raman scattering influenced by magnetic proximity effects.

We conduct experimental studies on the electrical transport properties of monolayer graphene directly covered by a few layers of CrI3. We do not observe the expected magnetic exchange coupling in the graphene but instead discover proximity effects featuring gate and magnetic field tunability. The tunability of gate voltage is manifested in the alignment of the lowest conduction band of CrI3 and the Fermi level of graphene, which can be controlled by the gate voltage. The coexistence of the normal and atypical quantum Hall effects in our device also corresponds to gate-control modulation doping. The lowest conduction band depends on the magnetic states of the CrI3 and can be altered by the magnetic field, which corresponds to the resistance loops during back-and-forth sweeps of the magnetic field. Our results serve as a reference for exploiting the magnetic proximity effects in graphene.

Blood, a ubiquitous and fundamental carbohydrate material composed of plasma, red blood cells, white blood cells, and platelets, has been playing an important role in biology, life science, history, and religious study, while graphene has garnered significant attention due to its exceptional properties and extensive range of potential applications. Achieving environmentally friendly, cost-effective growth using hybrid precursors and obtaining high-quality graphene through a straightforward CVD process has been traditionally considered mutually exclusive. This study demonstrates that we can produce high-quality graphene domains with controlled thickness through a one-step growth process at atmospheric pressure using blood as a precursor. Raman spectroscopy confirms the uniformity of the blood-grown graphene films, and observing the half-integer quantum Hall effect in the measured devices highlights its outstanding electronic properties. This unprecedented approach opens possibilities for blood application, facilitating an unconventional route in graphene growth applications.

Hybrid structures consisting of two-dimensional (2D) magnets and semiconductors have exhibited extensive functionalities in spintronics and opto-spintronics. In this work, we have fabricated WSe2/Fe3GeTe2 van der Waals heterostructures and investigated proximity effects on 2D magnetism. Through reflective magnetic circular dichroism, we have observed a temperature-dependent modulation of magnetic order in the heterostructure. For temperatures above 40 K , WSe2-covered Fe3GeTe2 exhibits a larger coercive field than that observed in bare Fe3GeTe2, accompanied by a noticeable enhancement of the Curie temperature by 21 K . This strengthening suggests an increase in magnetic anisotropy in the interfacial Fe3GeTe2 layer, which can be attributed to the spin-orbit coupling (SOC) proximity effect induced by the adjacent WSe2 layers. However, at much lower temperatures (T < 20 K ), a non-monotonic modification of the coercive field is observed, showing both reduction and enhancement, which depends on the thickness of the WSe2 and Fe3GeTe2 layers. Moreover, an unconventional two-step magnetization process emerges in the heterostructure, indicating the short-range nature of SOC proximity effects. Our findings on proximity coupling may shed light on the design of future spintronic and memory devices based on 2D magnetic heterostructures.

Two-dimensional ferroelectrics can maintain vertical polarization up to room temperature, and are, therefore, promising for next-generation nonvolatile memories. Although natural two-dimensional ferroelectrics are few, moiré superlattices provide us with a generalized method to construct ferroelectrics from non-ferroelectric parent materials. We report a realization of ferroelectric hysteresis in a AB-BA stacked twisted double bilayer graphene (TDBG) system. The ferroelectric polarization is prominent at zero external displacement field and reduces upon increasing displacement fields. TDBG in the AB-BA configuration possesses a superlattice of non-centrosymmetric domains, exhibiting alternatively switchable polarities even without the assistance of any boron nitride layers; however, in the AB-AB stacking case, the development of polarized domains necessitates the presence of a second superlattice induced by the adjacent boron nitride layer. Therefore, twisted multilayer graphene systems offer us a fascinating field to explore two-dimensional ferroelectricity.

We conduct experimental studies on the electrical transport properties of monolayer graphene directly covered by a few layers of CrI_3. We do not observe the expected magnetic exchange coupling in the graphene but instead discover proximity effects featuring gate and magnetic field tunability. The tunability of gate voltage is manifested in the alignment of the lowest conduction band of CrI_3 and the Fermi level of graphene, which can be controlled by the gate voltage. The coexistence of the normal and atypical quantum Hall effects in our device also corresponds to gate-control modulation doping. The lowest conduction band depends on the magnetic states of the CrI_3 and can be altered by the magnetic field, which corresponds to the resistance loops during back-and-forth sweeps of the magnetic field. Our results serve as a reference for exploiting the magnetic proximity effects in graphene.

CuSe monolayer possesses intrinsically patterned triangular nanopores with uniform size and can serve as a template for selective adsorptions for molecules and nanoclusters. Here, we prepare the CuSe monolayer on Cu(111) substrate by molecular beam epitaxy method and characterize CuSe monolayer in detail by bond-resolved scanning tunneling microscopy and non-contact atomic force microscopy. The results further confirm the honeycomb feature and triangular nanopores existence of CuSe monolayer. In addition, scanning tunneling spectroscopy measurements reveal the semiconducting features of CuSe monolayer with a band gap of 2.40 eV. This work helps to understand the structure and electronic properties of those intrinsically patterned two-dimensional materials.

Cu 2 Se monolayer (ML) synthesized experimentally is a member of transition metal chalcogenides materials, which has attracted significant attention due to its diversity and unique properties. However, the feature of an indirect band gap of Cu 2 Se ML in the low-temperature phase limits its’ application in electronics devices. Our study results based on the first principle calculations show that indirect-direct band gap transitions can occur in Cu 2 Se ML under appropriate uniaxial or biaxial strains. The band gap of Cu 2 Se ML is controllable due to the different responses of the edge-states near the Fermi level to the strain. The phonon dispersion suggests that the semiconducting Cu 2 Se ML can maintain dynamic stability in a wide range of strains. With the tunable electronic structure, semiconducting Cu 2 Se ML would become a promising candidate for electronic devices.

C-H bond activation and dehydrogenative coupling reactions have always been significant approaches to construct microscopic nanostructures on surfaces. By using scanning tunneling microscopy/spectroscopy (STM/STS) and non-contact atomic force microscopy (nc-AFM) combined with density functional theory (DFT), we systematically characterized the atomically precise topographies and electronic properties of H2TPP cyclodehydrogenation products on Au(111). Through surface-assisted thermal excitation, four types of cyclodehydrogenation products were obtained and clearly resolved in the nc-AFM images. The electronic characterization depicts the predominant resonances and their spatial distributions of the four products.

2D covalent organic framework-1 (COF-1) membrane is a potential hydrogen storage material. The hydrogen storage capacity of Li-decorated COF-1 has been studied by first-principles calculation. The results show its hydrogen storage capacity has been improved significantly by Li decoration, which is 7.69 wt%. Then ab initio molecular dynamics simulations at 300 K have been carried out and the results show that 12 H2 molecules are stably absorbed on the double sides of COF-1 unit cell decorated by 6 Li atoms and the hydrogen storage capacity is 5.26 wt%.

The fascinating Dirac cone in honeycomb graphene, which underlies many unique electronic properties, has inspired the vast endeavors on pursuing new two-dimensional（2D） Dirac materials. Based on the density functional theory method,a 2D material Zn 3 Si 2 of honeycomb transition-metal silicide with intrinsic Dirac cones has been predicted. The Zn 3 Si 2 monolayer is dynamically and thermodynamically stable under ambient conditions. Importantly, the Zn 3 Si 2 monolayer is a room-temperature 2D Dirac material with a spin–orbit coupling energy gap of 1.2 me V, which has an intrinsic Dirac cone arising from the special hexagonal lattice structure. Hole doping leads to the spin polarization of the electron, which results in a Dirac half-metal feature with single-spin Dirac fermion. This novel stable 2D transition-metal-silicon-framework material holds promises for electronic device applications in spintronics.

Using the 5,5′-dibromo-2,2′-bithiophene (DBBT) precursor, we successfully fabricated high-quality polythiophene chains on Au(111) substrates via a versatile on-surface chemical synthetic route. The DBBT precursor self-assembly behaviors and the formed polythiophene chains have been characterized by scanning tunneling microscopy experiments and density functional theory calculations. The results show that the polythiophene chains can form a wide variety of conformational isomers, owing to the fact that each thiophene group rotates randomly around the σ bond axis between two thiophene units. This work provides a new route toward constructing polythiophene and related substitutes on surfaces.

We show that in gapped bilayer graphene, quasiparticle tunneling and the corresponding Berry phase can be controlled such that they exhibit features of single-layer graphene such as Klein tunneling. The Berry phase is detected by a high-quality Fabry-Pérot interferometer based on bilayer graphene. By raising the Fermi energy of the charge carriers, we find that the Berry phase can be continuously tuned from 2π down to 0.68π in gapped bilayer graphene, in contrast to the constant Berry phase of 2π in pristine bilayer graphene. Particularly, we observe a Berry phase of π, the standard value for single-layer graphene. As the Berry phase decreases, the corresponding transmission probability of charge carriers at normal incidence clearly demonstrates a transition from anti-Klein tunneling to nearly perfect Klein tunneling.