Engineering Polar Vortices via Strain Soliton Interactions in Marginally Twisted Multilayer Graphene.

Strain solitons have been widely observed in van der Waals materials and their heterostructures. They can manifest as one-dimensional (1D) wires and quasi-two-dimensional (2D) networks. However, their coexistence within the same region has rarely been observed, and their interplay remains unexplored.

Interfacial Elemental Analysis of Slanted Edge-Contacted Monolayer MoS Transistors via Directionally Angled Etching.

Edge contacts offer a significant advantage for enhancing the performance of semiconducting transition metal dichalcogenide (TMDC) devices by interfacing with the metallic contacts on the lateral side, which allows the encapsulation of all of the channel material. However, despite intense research, the fabrication of feasible electrical edge contacts to TMDCs to improve device performance remains a great challenge, as interfacial chemical characterization via conventional methods is lacking. A major bottleneck in explicitly understanding the chemical and electronic properties of the edge contact at the metal-two-dimensional (2D) semiconductor interface is the small cross section when characterizing nominally one-dimensional edge contacts.

Photogenerated charge carrier dynamics on Pt-loaded SrTiO nanoparticles studied transient-absorption spectroscopy.

Loading cocatalysts on semiconductor-based photocatalysts to create active reaction sites is a preferable method to enhance photocatalytic activity and a widely adopted strategy to achieve effective photocatalytic applications. Although theoretical calculations suggest that the broad density of states of noble metal cocatalysts, such as Pt, act as a recombination center, this has never been experimentally demonstrated. Herein, we employed pico-nano and nano-micro second transient absorption spectroscopy to investigate the often overlooked photogenerated holes, instead of the widely studied electrons on Pt- and Ni-loaded SrTiO to evaluate the effects of cocatalysts as a recombination center.

Electrical Control of Photoluminescence in 2D Semiconductors Coupled to Plasmonic Lattices.

Integrating two-dimensional (2D) semiconductors into nanophotonic structures provides a versatile platform for advanced optoelectronic devices. A key challenge in realizing these systems is to achieve control over light emission from these materials. In this work, we demonstrate the modulation of photoluminescence (PL) in transition metal dichalcogenides (TMDs) coupled to surface lattice resonances in metal nanoparticle arrays.

Continuous Strain Modulation of Moiré Superlattice Symmetry From Triangle to Rectangle.

Moiré superlattices formed in van der Waals (vdW) bilayers of 2D materials provide an ideal platform for studying previously undescribed physics, including correlated electronic states and moiré excitons, owing to the wide-range tunability of their lattice constants. However, their crystal symmetry is fixed by the monolayer structure, and the lack of a straightforward technique for modulating the symmetry of moiré superlattices has impeded progress in this field. Herein, a simple, room-temperature, ambient method for controlling superlattice symmetry is reported.

Ultrasmall α-MnO with Low Aspect Ratio: Applications to Electrochemical Multivalent-Ion Intercalation Hosts and Aerobic Oxidation Catalysts.

Hollandite-type α-MnO exhibits exceptional promise in current industrial applications and in advancing next-generation green energy technologies, such as multivalent (Mg, Ca, and Zn) ion battery cathodes and aerobic oxidation catalysts. Considering the slow diffusion of multivalent cations within α-MnO tunnels and the catalytic activity at edge surfaces, ultrasmall α-MnO particles with a lower aspect ratio are expected to unlock the full potential. In this study, ultrasmall α-MnO (<10 nm) with a low aspect ratio (c/a ≈ 2) is synthesized using a newly developed alcohol solution process.

formation of ultrahigh molecular weight polymers in highly concentrated electrolytes and their physicochemical properties.

We developed a facile one-pot method for fabricating physical gels consisting of ultrahigh molecular weight (UHMW) polymers and highly concentrated lithium salt electrolytes. We previously reported physical gels formed from the entanglement of UHMW polymers by radical polymerisation in aprotic ionic liquids. In this study, we found that the molecular weight of methacrylate polymers formed by radical polymerisation increased with the concentration of lithium salts in the organic solvents.

Low-Frequency Resistance Noise in Near-Magic-Angle Twisted Bilayer Graphene.

The low-frequency resistance fluctuations, or noise, in electrical resistance not only set a performance benchmark in devices but also form a sensitive tool to probe nontrivial electronic phases and band structures in solids. Here, we report the measurement of such noise in the electrical resistance in twisted bilayer graphene (tBLG), where the layers are misoriented close to the magic angle (θ ∼ 1°). At high temperatures ( ≳ 60-70 K), the power spectral density (PSD) of the fluctuation inside the low-energy moiré bands is predominantly ∝1/, where is the frequency, being generally lowest close to the magic angle, and can be well-explained within the conventional McWhorter model of the '1/ noise' with trap-assisted density-mobility fluctuations.

Nanosecond Nanothermometry in an Electron Microscope.

Thermal transport in nanostructures plays a critical role in modern technologies. As devices shrink, techniques that can measure thermal properties at nanometer and nanosecond scales are increasingly needed to capture transient, out-of-equilibrium phenomena. We present a novel pump-probe photon-electron method within a scanning transmission electron microscope (STEM) to map temperature dynamics with unprecedented spatial and temporal resolutions.

Ferroelectricity with concomitant Coulomb screening in van der Waals heterostructures.

Interfacial ferroelectricity emerges in non-centrosymmetric heterostructures consisting of non-polar van der Waals (vdW) layers. Ferroelectricity with concomitant Coulomb screening can switch topological currents or superconductivity and simulate synaptic response. So far, it has only been realized in bilayer graphene moiré superlattices, posing stringent requirements to constituent materials and twist angles.

Pressure-Induced Dehydration and Reversible Recrystallization of Dihydrogen-Bonded Sodium Borohydride Dihydrate NaBH·2HO.

Sodium borohydride dihydrate (NaBH·2HO) forms through dihydrogen bonding between the hydridic hydrogen of the BH ion and the protonic hydrogen of the water molecule. High-pressure structural changes in NaBH·2HO, observed up to 11 GPa through X-ray diffraction and Raman scattering spectroscopy, were analyzed to assess the influence of dihydrogen bonds on its crystal structure. At approximately 4.

Identification of Two-Dimensional Interlayer Excitons and Their Valley Polarization in MoSe/WSe Heterostructure with -BN Spacer Layer.

Interlayer excitons (IXs) in the heterostructure of monolayer transition metal dichalcogenides (TMDs) are considered as a promising platform to study fundamental exciton physics and for potential applications of next generation optoelectronic devices. The IXs trapped in the moiré potential in a twisted monolayer TMD heterostructure such as MoSe/WSe form zero-dimensional (0D) moiré excitons. Introducing an atomically thin insulating layer between TMD monolayers in a twisted heterostructure would modulate the moiré potential landscape, thereby tuning 0D IXs into 2D IXs.

Electrically Pumped -BN Single-Photon Emission in van der Waals Heterostructure.

Atomic defects in solids offer a versatile basis to study and realize quantum phenomena and information science in various integrated systems. All-electrical pumping of single defects to create quantum light emission has been realized in several platforms including color centers in diamond and silicon carbide, which could lead to the circuit network of electrically triggered single-photon sources. However, a wide conduction channel which reduces the carrier injection per defect site has been a major obstacle.

Ammonia Decomposition Catalyzed by Co Nanoparticles Encapsulated in Rare Earth Oxide.

We fabricated Co-based catalysts by the low-temperature thermal decomposition of R-Co intermetallics (R = Y, La, or Ce) to reduce the temperature of ammonia cracking for hydrogen production. The catalysts synthesized are nanocomposites of Co/RO with a metal-rich composition. In the Co/LaO catalyst derived from LaCo, Co nanoparticles of 10-30 nm size are enclosed by the LaO matrix.

Electrically Switching Ferroelectric Order in 3R-MoS Layers.

Transition metal dichalcogenides (TMDs) with rhombohedral (3R) stacking order are excellent platforms to realize multiferroelectricity. In this work, we demonstrate the electrical switching of ferroelectric orders in bilayer, trilayer, and tetralayer 3R-MoS dual-gate devices by examining their reflection and photoluminescence (PL) responses under sweeping out-of-plane electric fields. We observe sharp shifts in excitonic spectra at different critical fields with pronounced hysteresis.

Histochemical analysis of osteoclast and osteoblast distributions on hydroxyapatite/collagen bone-like nanocomposite embedded in rat tibiae.

Objectives: Hydroxyapatite (HAp)/collagen (Col) cylinders with laminated collagen layers were implanted into the tibial diaphysis of rats and examined histochemically to clarify how the orientation of HAp and Col bone-like nanocomposite fibers in HAp/Col blocks affects bone resorption and formation.

Methods: HAp/Col fibers were synthesized and compressed into cylindrical blocks to mimic bone nanostructures. These were implanted into the cortical bone cavities of 10-week-old male Wistar rats with fiber bundles parallel to the tibial surface.

Pick-and-Place Transfer of Arbitrary-Metal Electrodes for van der Waals Device Fabrication.

Van der Waals electrode integration is a promising strategy to create nearly perfect interfaces between metals and 2D materials, with advantages such as eliminating Fermi-level pinning and reducing contact resistance. However, the lack of a simple, generalizable pick-and-place transfer technology has greatly hampered the wide use of this technique. We demonstrate the pick-and-place transfer of prefabricated electrodes from reusable polished hydrogenated diamond substrates without the use of any sacrificial layers due to the inherent low-energy and dangling-bond-free nature of the hydrogenated diamond surface.

The effect of microenvironmental viscosity on the emergence of colon cancer cell resistance to doxorubicin.

The colon possesses a unique physiological environment among human organs, where there is a highly viscous body fluid layer called the mucus layer above colonic epithelial cells. Dysfunction of the mucus layer not only contributes to the occurrence of colorectal cancer (CRC) but also plays an important role in the development of chemoresistance in CRC. Although viscosity is an essential property of the mucus layer, it remains elusive how viscosity affects chemoresistance in colon cancer cells.

High-throughput evaluation of half-metallicity of CoMnSi Heusler alloys using composition-spread films and spin-integrated hard X-ray photoelectron spectroscopy.

We demonstrate high-throughput evaluation of the half-metallicity of CoMnSi Heusler alloys by spin-integrated hard X-ray photoelectron spectroscopy (HAXPES) of composition-spread films performed with high-brilliance synchrotron radiation at NanoTerasu, which identifies the optimum composition showing the best half-metallicity. Co Mn Si composition-spread thin films for  = 10-40% with a thickness of 30 nm are fabricated on MgO(100) substrates using combinatorial sputtering technique. The 2-ordering and (001)-oriented epitaxial growth of CoMnSi are confirmed by X-ray diffraction for  = 18-40%.

Fine-Tuning of the Sequential Self-Assembly of Entangled Polyhedra by Exploiting the Side-Chain Effect.

The control of the sequential self-assembly processes of highly entangled (AgL) (n=2,4,6,8) and AgL coordination polyhedra using side-chain effects was studied via the introduction of linear or branched side chains into the tripodal ligands. In addition to changes in the intermediate polyhedral species affording the multi- pathway process, disruption of the kinetic control of the sequential self-assembly was observed, thus demonstrating the utility of steric control for the construction of 3D-entangled molecular materials on the 5 nm scale with high molecular complexity.

Rational design of redox active metal organic frameworks for mediated electron transfer of enzymes.

The efficient immobilization of redox mediators remains a major challenge in the design of mediated enzyme electrode platforms. In addition to stability, the ability of the redox-active material to mediate electron transfer from the active-site buried enzymes, such as flavin adenine dinucleotide-dependent glucose dehydrogenase (FADGDH) and lactate oxidase (LOx), is also crucial. Conventional immobilization techniques can be synthetically challenging, and immobilized mediators often exhibit limited durability, particularly in continuous operation.

Time-domain signatures of distinct correlated insulators in a moiré superlattice.

Among expanding discoveries of quantum phases in moiré superlattices, correlated insulators stand out as both the most stable and most commonly observed. Despite the central importance of these states in moiré physics, little is known about their underlying nature. Here, we use pump-probe spectroscopy to show distinct time-domain signatures of correlated insulators at fillings of one (ν = -1) and two (ν = -2) holes per moiré unit cell in the angle-aligned WSe/WS system.

Direct View of Gate-Tunable Miniband Dispersion in Graphene Superlattices Near the Magic Twist Angle.

Superlattices from twisted graphene mono- and bilayer systems give rise to on-demand many-body states such as Mott insulators and unconventional superconductors. These phenomena are ascribed to a combination of flat bands and strong Coulomb interactions. However, a comprehensive understanding is lacking because the low-energy band structure strongly changes when an electric field is applied to vary the electron filling.

Regulation of antigen presentation and interleukin 10 production in murine dendritic cells via the oxidative stimulation of cell membrane using a polycation-porphyrin-conjugate-immobilized cell culture dish.

Tolerogenic dendritic cells with professional antigen presentation via major histocompatibility complex molecules, co-stimulatory molecules (CD80/86), and interleukin 10 production have attracted significant attention as cellular therapies for autoimmune, allergic, and graft-versus-host diseases. In this study, we developed a cell culture dish equipped with polycation-porphyrin-conjugate-immobilized glass (PA-HP-G) to stimulate immature murine dendritic cell (iDCs). Upon irradiation with a red light at 635 nm toward the PA-HP-G surface, singlet oxygen was generated by the immobilized porphyrins on the PA-HP-G surface.