Purcell-Induced Bright Single Photon Emitters in Hexagonal Boron Nitride.

Single photon emitters (SPEs) in hexagonal boron nitride (hBN) are elementary building blocks for room-temperature on-chip quantum photonic technologies. However, fundamental challenges, such as slow radiative decay and nondeterministic placement of the emitters, limit their full potential. Here, we demonstrate large-area arrays of plasmonic nanoresonators (PNRs) for Purcell-induced room-temperature SPEs by engineering emitter-cavity coupling and enhancing radiative emission.

Bonding-Directed Crystallization of Ultra-Long One-Dimensional NbS van der Waals Nanowires.

The rediscovery of one-dimensional (1D) and quasi-1D (q-1D) van der Waals (vdW) crystals ushered the realization of nascent physical properties in 1D that are suitable for applications in photonics, electronics, and sensing. However, despite renewed interest in the creation and understanding of the physical properties of 1D and q-1D vdW crystals, the lack of accessible synthetic pathways for growing well-defined nanostructures that extend across several length scales remains. Using the highly anisotropic 1D vdW NbS-I crystal as a model phase, we present a catalyst-free and bottom-up synthetic approach to access ultralong nanowires, with lengths reaching up to 7.

Unravelling the novel sex determination genotype with 'ZY' and a distinctive 2.15-2.95 Mb inversion among poplar species through haplotype-resolved genome assembly and comparative genomics analysis.

Populus tomentosa, an indigenous tree species, is widely distributed and cultivated over 1,000,000 km in China, contributing significantly to forest production, ecological conservation and urban-rural greening. Although a reference genome is available for P. tomentosa, the intricate interspecific hybrid origins, chromosome structural variations (SVs) and sex determination mechanisms remain confusion and unclear due to its broad and even overlapping geographical distribution, extensive morphological variations and cross infiltration among white poplar species.

Persistent Chirality-Induced Spin-Selectivity Effect in Circular Helix Molecules.

The spin-orbit coupling (SOC), the dynamics of the nonequilibrium transport process, and the breaking of time-reversal and space-inversion symmetries have been regarded as key factors for the emergence of chirality-induced spin selectivity (CISS) and chirality-dependent spin currents in helix molecules. In this work, we demonstrated the generation of persistent CISS currents in various circular single-stranded DNAs and 3-helix proteins for the first time, regardless of whether an external magnetic flux is applied or not. This new CISS effect presents only in equilibrium transport processes, distinct from the traditional CISS observed in nonequilibrium transport processes and linear helix molecules; we term it as the PCISS effect.

Origin of Interfacial Orbital Reconstruction in Perovskite Superlattices.

The competition between on-site electronic correlation and local crystal field stands out as a captivating topic in research. However, its physical ramifications often get overshadowed by influences of strong periodic potential and orbital hybridization. The present study reveals this competition may become more pronounced or even dominant in two-dimensional systems, driven by the combined effects of dimensional confinement and orbital anisotropy.

Switching Intrinsic Magnetic Skyrmions with Controllable Magnetic Anisotropy in van der Waals Multiferroic Heterostructures.

Magnetic skyrmions, topologically nontrivial whirling spin textures at nanometer scales, have emerged as potential information carriers for spintronic devices. The ability to efficiently create and erase magnetic skyrmions is vital yet challenging for such applications. Based on first-principles studies, we find that switching between intrinsic magnetic skyrmion and high-temperature ferromagnetic states can be achieved in the two-dimensional van der Waals (vdW) multiferroic heterostructure CrSeI/InTe by reversing the ferroelectric polarization of InTe.

Tunable quantum anomalous Hall effects in ferromagnetic van der Waals heterostructures.

The quantum anomalous Hall effect (QAHE) has unique advantages in topotronic applications, but it is still challenging to realize the QAHE with tunable magnetic and topological properties for building functional devices. Through systematic first-principles calculations, we predict that the in-plane magnetization induced QAHE with Chern numbers  = ±1 and the out-of-plane magnetization induced QAHE with high Chern numbers  = ±3 can be realized in a single material candidate, which is composed of van der Waals (vdW) coupled Bi and MnBiTe monolayers. The switching between different phases of QAHE can be controlled in multiple ways, such as applying strain or (weak) magnetic field or twisting the vdW materials.

Sensitive Thermochromic Behavior of InSeI, a Highly Anisotropic and Tubular 1D van der Waals Crystal.

Thermochromism, the change in color of a material with temperature, is the fundamental basis of optical thermometry. A longstanding challenge in realizing sensitive optical thermometers for widespread use is identifying materials with pronounced thermometric optical performance in the visible range. Herein, it is demonstrated that single crystals of indium selenium iodide (InSeI), a 1D van der Waals (vdW) solid consisting of weakly bound helical chains, exhibit considerable visible range thermochromism.

Atomic-scale origin of the low grain-boundary resistance in perovskite solid electrolyte LiSrTaZrO.

Oxide solid electrolytes (OSEs) have the potential to achieve improved safety and energy density for lithium-ion batteries, but their high grain-boundary (GB) resistance generally is a bottleneck. In the well-studied perovskite oxide solid electrolyte, LiLaTiO (LLTO), the ionic conductivity of grain boundaries is about three orders of magnitude lower than that of the bulk. In contrast, the related LiSrTaZrO (LSTZ0.

Electrically Tunable Topological Phase Transition in van der Waals Heterostructures.

The realization and control of the quantum anomalous Hall (QAH) effect are highly desirable for the development of spintronic and quantum devices. In this work, we propose a van der Waals (vdW) heterostructure of ultrathin MnBiSe and BiSe layers and demonstrate that it is an excellent tunable QAH platform by using model Hamiltonian and density functional theory simulations. Its band gap closes and reopens as external electric field increases, manifesting a novel topological phase transition with an electric field of ∼0.

Electrical Manipulation of Topological Phases in a Quantum Anomalous Hall Insulator.

Quantum anomalous Hall phases arising from the inverted band topology in magnetically doped topological insulators have emerged as an important subject of research for quantization at zero magnetic fields. Though necessary for practical implementation, sophisticated electrical control of molecular beam epitaxy (MBE)-grown quantum anomalous Hall matter have been stymied by growth and fabrication challenges. Here, a novel procedure is demonstrated, employing a combination of thin-film deposition and 2D material stacking techniques, to create dual-gated devices of the MBE-grown quantum anomalous Hall insulator, Cr-doped (Bi,Sb) Te .

Curvature-Induced One-Dimensional Phonon Polaritons at Edges of Folded Boron Nitride Sheets.

Generation and manipulation of phonon polaritons are of paramount importance for understanding the interaction between an electromagnetic field and dielectric materials and furthering their application in mid-infrared optical communication. However, the formation of tunable one-dimensional phonon polaritons has been rarely realized in van der Waals layered structures. Here we report the discovery of curvature-induced phonon polaritons localized at the crease of folded hexagonal boron nitrides (-BNs) with a few atomic layers using monochromated electron energy-loss spectroscopy.

Distinguishing the Two-Component Anomalous Hall Effect from the Topological Hall Effect.

In transport, the topological Hall effect (THE) presents itself as nonmonotonic features (or humps and dips) in the Hall signal and is widely interpreted as a sign of chiral spin textures, like magnetic skyrmions. However, when the anomalous Hall effect (AHE) is also present, the coexistence of two AHEs could give rise to similar artifacts, making it difficult to distinguish between genuine THE with AHE and two-component AHE. Here, we confirm genuine THE with AHE by means of transport and magneto-optical Kerr effect (MOKE) microscopy, in which magnetic skyrmions are directly observed, and find that genuine THE occurs in the transition region of the AHE.

Nanoscale imaging of phonon dynamics by electron microscopy.

Spatially resolved vibrational mapping of nanostructures is indispensable to the development and understanding of thermal nanodevices, modulation of thermal transport and novel nanostructured thermoelectric materials. Through the engineering of complex structures, such as alloys, nanostructures and superlattice interfaces, one can significantly alter the propagation of phonons and suppress material thermal conductivity while maintaining electrical conductivity. There have been no correlative experiments that spatially track the modulation of phonon properties in and around nanostructures due to spatial resolution limitations of conventional optical phonon detection techniques.

Electronic Structure of de Novo Peptide ACC-Hex from First Principles.

Proteins are promising components for bioelectronic devices due in part to their biocompatibility, flexibility, and chemical diversity, which enable tuning of material properties. Indeed, an increasingly broad range of conductive protein supramolecular materials have been reported. However, due to their structural and environmental complexity, the electronic structure, and hence conductivity, of protein assemblies is not well-understood.

Identification and Validation of Reliable Reference Genes for Gene Expression Studies in .

RT-qPCR is considered a rapid and reliable technique for analyzing gene expression. This technique is commonly used to analyze the expression of various genes at diverse transcriptional levels in different samples. However, few studies have characterized ornamental species for reliable reference genes.

Confinement-Induced Catalytic Dissociation of Hydrogen Molecules in a Scanning Tunneling Microscope.

The catalytic scission of single chemical bonds has been induced by the nanoscale confinement in a scanning tunneling microscope (STM) junction. Individual hydrogen molecules sandwiched between the STM tip and a copper substrate can be dissociated solely by the reciprocating movement of the tip. The reaction rate depends sensitively on the local molecular environment, as exemplified by the effects of a nearby carbon monoxide molecule or a gold adatom.

Bias-tunable two-dimensional magnetic and topological materials.

The search for novel two-dimensional (2D) materials is crucial for the development of next generation technologies such as electronics, optoelectronics, electrochemistry and biomedicine. In this work, we designed a series of 2D materials based on endohedral fullerenes and revealed that many of them integrate different functions in a single system, such as ferroelectricity with large electric dipole moments, multiple magnetic phases with both strong magnetic anisotropy and high Curie temperature, and quantum spin Hall effect or quantum anomalous Hall effect with robust topologically protected edge states. We further proposed a new type of topological field-effect transistor.

Robust cortical criticality and diverse dynamics resulting from functional specification.

Despite the recognition of the layered structure and evident criticality in the cortex, how the specification of input, output, and computational layers affects the self-organized criticality has not been much explored. By constructing heterogeneous structures with a well-accepted model of leaky neurons, we find that the specification can lead to robust criticality rather insensitive to the strength of external stimuli. This naturally unifies the adaptation to strong inputs without extra synaptic plasticity mechanisms.

Single-defect phonons imaged by electron microscopy.

Crystal defects affect the thermal and heat-transport properties of materials by scattering phonons and modifying phonon spectra. To appreciate how imperfections in solids influence thermal conductivity and diffusivity, it is thus essential to understand phonon-defect interactions. Sophisticated theories are available to explore such interactions, but experimental validation is limited because most phonon-detecting spectroscopic methods do not reach the high spatial resolution needed to resolve local vibrational spectra near individual defects.