Switchable Quantized Signal between Longitudinal Conductance and Hall Conductance in Dual Quantum Spin Hall Insulator TaIrTe.

Topological insulating states in 2-dimensional (2D) materials are ideal systems to study different types of quantized response signals due to their in gap metallic states. Very recently, the quantum spin Hall effect was discovered in monolayer TaIrTe via the observation of quantized longitudinal conductance that rarely exists in other 2D topological insulators. The nontrivial topological charges can exist at both charge neutrality point and the van Hove singularity point with correlation-effect-induced bandgap.

Intercalating Architecture for the Design of Charge Density Wave in Metallic MAZ Materials.

We present a novel approach to induce charge density waves (CDWs) in metallic MAZ materials, resembling the behavior observed in transition metal dichalcogenides (TMDCs). This method leverages the intercalating architecture to maintain the same crystal field and Fermi surface topologies. Our investigation reveals that CDW instability in these materials arises from electron-phonon coupling (EPC) between the band and longitudinal acoustic (LA) phonons, mirroring TMDC's behavior.

Van der Waals polarity-engineered 3D integration of 2D complementary logic.

Vertical three-dimensional integration of two-dimensional (2D) semiconductors holds great promise, as it offers the possibility to scale up logic layers in the z axis. Indeed, vertical complementary field-effect transistors (CFETs) built with such mixed-dimensional heterostructures, as well as hetero-2D layers with different carrier types, have been demonstrated recently. However, so far, the lack of a controllable doping scheme (especially p-doped WSe (refs.

Layer-by-layer phase transformation in TiO revealed by machine-learning molecular dynamics simulations.

Reconstructive phase transitions involving breaking and reconstruction of primary chemical bonds are ubiquitous and important for many technological applications. In contrast to displacive phase transitions, the dynamics of reconstructive phase transitions are usually slow due to the large energy barrier. Nevertheless, the reconstructive phase transformation from β- to λ-TiO exhibits an ultrafast and reversible behavior.

Phonon stability boundary and deep elastic strain engineering of lattice thermal conductivity.

Recent studies have reported the experimental discovery that nanoscale specimens of even a natural material, such as diamond, can be deformed elastically to as much as 10% tensile elastic strain at room temperature without the onset of permanent damage or fracture. Computational work combining ab initio calculations and machine learning (ML) algorithms has further demonstrated that the bandgap of diamond can be altered significantly purely by reversible elastic straining. These findings open up unprecedented possibilities for designing materials and devices with extreme physical properties and performance characteristics for a variety of technological applications.

Dual-Mode Conversion of Photodetector and Neuromorphic Vision Sensor via Bias Voltage Regulation on a Single Device.

Simultaneous implementation of photodetector and neuromorphic vision sensor (NVS) on a single device faces a great challenge, due to the inherent speed discrepancy in their photoresponse characteristics. In this work, a trench-bridged GaN/Ga O /GaN back-to-back double heterojunction array device is fabricated to enable the advanced functionalities of both devices on a single device. Interestingly, the device shows fast photoresponse and persistent photoconductivity behavior at low and high voltages, respectively, through the modulation of oxygen vacancy ionization and de-ionization processes in Ga O .

Direct Observation of Topological Phonons in Graphene.

Phonons, as the most fundamental emergent bosons in condensed matter systems, play an essential role in the thermal, mechanical, and electronic properties of crystalline materials. Recently, the concept of topology has been introduced to phonon systems, and the nontrivial topological states also exist in phonons due to the constraint by the crystal symmetry of the space group. Although the classification of various topological phonons has been enriched theoretically, experimental studies were limited to several three-dimensional (3D) single crystals with inelastic x-ray or neutron scatterings.

Flatband λ-TiO towards extraordinary solar steam generation.

Solar steam interfacial evaporation represents a promising strategy for seawater desalination and wastewater purification owing to its environmentally friendly character. To improve the solar-to-steam generation, most previous efforts have focused on effectively harvesting solar energy over the full solar spectrum. However, the importance of tuning joint densities of states in enhancing solar absorption of photothermal materials is less emphasized.

Large Spin Hall Conductivity and Excellent Hydrogen Evolution Reaction Activity in Unconventional PtTe Monolayer.

Two-dimensional (2D) materials have gained lots of attention due to the potential applications. In this work, we propose that based on first-principles calculations, the (2 × 2) patterned PtTe monolayer with kagome lattice formed by the well-ordered Te vacancy (PtTe) hosts large and tunable spin Hall conductivity (SHC) and excellent hydrogen evolution reaction (HER) activity. The unconventional nature relies on the 1 @ 1 band representation of the highest valence band without spin-orbit coupling (SOC).

Two-dimensional superconducting MoSiN(MoN) homologous compounds.

The number and stacking order of layers are two important degrees of freedom that can modulate the properties of 2D van der Waals (vdW) materials. However, the layers' structures are essentially limited to the known layered 3D vdW materials. Recently, a new 2D vdW material, MoSiN, without known 3D counterparts, was synthesized by passivating the surface dangling bonds of non-layered 2D molybdenum nitride with elemental silicon, whose monolayer can be viewed as a monolayer MoN (-N-Mo-N-) sandwiched between two Si-N layers.

Low-oxygen rare earth steels.

Rare earth (RE) addition to steels to produce RE steels has been widely applied when aiming to improve steel properties. However, RE steels have exhibited extremely variable mechanical performances, which has become a bottleneck in the past few decades for their production, utilization and related study. Here in this work, we discovered that the property variation of RE steels stems from the presence of oxygen-based inclusions.

One-Step Growth of Bilayer 2H-1T' MoTe van der Waals Heterostructures with Interlayer-Coupled Resonant Phonon Vibration.

2H-1T' MoTe van der Waals heterostructures (vdWHs) have promising applications in optoelectronics due to a seamlessly homogeneous semiconductor-metal coupled interface. However, the existing methods to fabricate such vdWHs involved complicated steps that may deteriorate the interfacial coupling and are also lacking precise thickness control capability. Here, a one-step growth method was developed to controllably grow bilayer 2H-1T' MoTe vdWHs in the small growth window overlapped for both phases.

Manufacture-friendly nanostructured metals stabilized by dual-phase honeycomb shell.

Refining grains to the nanoscale can greatly enhance the strength of metals. But the engineering applications of nanostructured metals are limited by their complex manufacturing technology and poor microstructural stability. Here we report a facile "Eutectoid element alloying→ Quenching→ Hot deformation" (EQD) strategy, which enables the mass production of a Ti6Al4V5Cu (wt.

Two-dimensional layered MSiN (M = Mo, W) as promising thermal management materials: a comparative study.

With the miniaturization and integration of nanoelectronic devices, efficient heat removal becomes a key factor affecting their reliable operation. Two-dimensional (2D) materials, with high intrinsic thermal conductivity, good mechanical flexibility, and precisely controllable growth, are widely accepted as ideal candidates for thermal management materials. In this work, by solving the phonon Boltzmann transport equation (BTE) based on first-principles calculations, we investigated the thermal conductivity of novel 2D layered MSiN (M = Mo, W).

Six-membered-ring inorganic materials: definition and prospects.

The six-membered ring (SMR) is a common structure unit for numerous material systems. These materials include, but are not limited to, the typical two-dimensional materials such as graphene, -BN, and transition metal dichalcogenides, as well as three-dimensional materials such as beryllium, magnesium, MgB and BiSe. Although many of these materials have already become 'stars' in materials science and condensed-matter physics, little attention has been paid to the roles of the SMR unit across a wide range of compositions and structures.

Topological phononic materials: Computation and data.

Considering the current volume of materials data, it is impossible to investigate each compound by trial-and-error experiments involving labor-intensive efforts. The scientists in the Shenyang National Laboratory for Materials Science developed a home-made software, HT-PHONON, selecting over 5,000 topological phononic (TP) materials out of 13,000 materials within high-throughput computational materials design combined with a big data analysis. Furthermore, an online database for TP materials has been constructed, which is now freely open to the public community through the website www.

Intercalated architecture of MAZ family layered van der Waals materials with emerging topological, magnetic and superconducting properties.

The search for new two-dimensional monolayers with diverse electronic properties has attracted growing interest in recent years. Here, we present an approach to construct MAZ monolayers with a septuple-atomic-layer structure, that is, intercalating a MoS-type monolayer MZ into an InSe-type monolayer AZ. We illustrate this unique strategy by means of first-principles calculations, which not only reproduce the structures of MoSiN and MnBiTe that were already experimentally synthesized, but also predict 72 compounds that are thermodynamically and dynamically stable.

Computation and data driven discovery of topological phononic materials.

The discovery of topological quantum states marks a new chapter in both condensed matter physics and materials sciences. By analogy to spin electronic system, topological concepts have been extended into phonons, boosting the birth of topological phononics (TPs). Here, we present a high-throughput screening and data-driven approach to compute and evaluate TPs among over 10,000 real materials.

Coexistence of intrinsic piezoelectricity and ferromagnetism induced by small biaxial strain in septuple-atomic-layer VSiP.

The septuple-atomic-layer VSi2P4 with the same structure of experimentally synthesized MoSi2N4 is predicted to be a spin-gapless semiconductor (SGS) with the generalized gradient approximation (GGA). In this work, the biaxial strain is applied to tune the electronic properties of VSi2P4, and it spans a wide range of properties upon increasing the strain from a ferromagnetic metal (FMM) to SGS to a ferromagnetic semiconductor (FMS) to SGS to a ferromagnetic half-metal (FMHM). Due to broken inversion symmetry, the coexistence of ferromagnetism and piezoelectricity can be achieved in FMS VSi2P4 with the strain range of 0% to 4%.

Thermoelectric performance of a metastable thin-film Heusler alloy.

Thermoelectric materials transform a thermal gradient into electricity. The efficiency of this process relies on three material-dependent parameters: the Seebeck coefficient, the electrical resistivity and the thermal conductivity, summarized in the thermoelectric figure of merit. A large figure of merit is beneficial for potential applications such as thermoelectric generators.

Underlying Topological Dirac Nodal Line Mechanism of the Anomalously Large Electron-Phonon Coupling Strength on a Be (0001) Surface.

Beryllium has recently been discovered to harbor a Dirac nodal line (DNL) in its bulk phase and the DNL-induced nontrivial surface states (DNSSs) on its (0001) surface, rationalizing several already-existing historic puzzles [Phys. Rev. Lett.

Flexible layer-structured BiTe thermoelectric on a carbon nanotube scaffold.

Inorganic chalcogenides are traditional high-performance thermoelectric materials. However, they suffer from intrinsic brittleness and it is very difficult to obtain materials with both high thermoelectric ability and good flexibility. Here, we report a flexible thermoelectric material comprising highly ordered BiTe nanocrystals anchored on a single-walled carbon nanotube (SWCNT) network, where a crystallographic relationship exists between the BiTe <[Formula: see text]> orientation and SWCNT bundle axis.

Noninvasively Modifying Band Structures of Wide-Bandgap Metal Oxides to Boost Photocatalytic Activity.

Although doping with appropriate heteroatoms is a powerful way of increasing visible light absorption of wide-bandgap metal oxide photocatalysts, the incorporation of heteroatoms into the photocatalysts usually leads to the increase of deleterious recombination centers of photogenerated charge carriers. Here, a conceptual strategy of increasing visible light absorption without causing additional recombination centers by constructing an ultrathin insulating heterolayer of amorphous boron oxynitride on wide-bandgap photocatalysts is shown. The nature of this strategy is that the active composition nitrogen in the heterolayer can noninvasively modify the electronic structure of metal oxides for visible light absorption through the interface contact between the heterolayer and metal oxides.