Accurate two-dimensional simulation model and experimental demonstration in ultraviolet picosecond laser scribing ablation.

Laser patterning of copper thin films is essential for the electronics manufacturing industry. In this work, to efficiently and accurately describe the physics process of UV-ps laser ablating copper thin film, a two-temperature model (TTM) consisting of the electron-lattice system and phase explosion mechanism was proposed. The process of electron heating and electron-lattice heat transfer in single pulse ablation were revealed.

Two-Dimensional Topological Platinum Telluride Superstructures with Periodic Tellurium Vacancies for Efficient and Robust Catalysis.

Defect engineering in the inherently inert basal planes of transition metal dichalcogenides (TMDs), involving the introduction of chalcogen vacancies, represents a pivotal approach to enhance catalytic activity by exposing high-density catalytic metal single-atom sites. However, achieving a single-atom limit spacing between chalcogen vacancies to form ordered superstructures remains challenging for creating uniformly distributed high-density metal single-atom sites on TMDs comparable to carbon-supported single-atom catalysts (SACs). Here we unveil an efficient TMD-based topological catalyst for hydrogen evolution reaction (HER), featuring high-density single-atom reactive centers on a few-layer (7 × 7)-PtTe superstructure.

Investigation of structural parameters influencing vibration characteristics of heavy-duty truck diesel tanks.

The working conditions of heavy-duty trucks are very complicated as the diesel shaking and resonance problems, which causes weld tears, separators to fall off, and other failures occur. Through experiments and finite element simulation, the natural frequency and vibration mode of a given 400 L diesel tank were calculated to study the influences of structural parameters such as the fill ratio (0.1-0.

Monolayer Borophene Formation on Cu(111) Surface Triggered by Step Edge.

Borophene, a promising material with potential applications in electronics, energy storage, and sensors, is successfully grown as a monolayer on Ag(111), Cu(111), and Au(111) surfaces using molecular beam epitaxy. The growth of two-dimensional borophene on Ag(111) and Au(111) is proposed to occur via surface adsorption and boron segregation, respectively. However, the growth mode of borophene on Cu(111) remains unclear.

Spectroscopic signature of obstructed surface states in SrInP.

The century-long development of surface sciences has witnessed the discoveries of a variety of quantum states. In the recently proposed "obstructed atomic insulators", symmetric charges are pinned at virtual sites where no real atoms reside. The cleavage through these sites could lead to a set of obstructed surface states with partial electronic occupation.

Dissociation dynamics of anionic carbon monoxide in dark states.

A resonant system consisting of an excess electron and a closed-shell atom or molecule, as a temporary negative ion, is usually in doublet-spin states that are analogous to bright states of photoexcitation of the neutral. However, anionic higher-spin states, noted as dark states, are scarcely accessed. Here, we report the dissociation dynamics of CO- in dark quartet resonant states that are formed by electron attachments to electronically excited CO (a3Π).

A Case of Fulminant Right Heart Failure Owing to Tumoral Pulmonary Hypertension.

Tumoral pulmonary hypertension is a rare cause of pulmonary hypertension. We report a patient who was thought to have idiopathic pulmonary arterial hypertension, but later developed fulminant right heart failure ultimately leading to death. Autopsy revealed substantial pulmonary tumor embolism burden originating from liver adenocarcinoma.

Charge instability of topological Fermi arcs in chiral crystal CoSi.

Topological boundary states emerged at the spatial boundary between topological non-trivial and trivial phases, are usually gapless, or commonly referred as metallic states. For example, the surface state of a topological insulator is a gapless Dirac state. These metallic topological boundary states are typically well described by non-interacting fermions.

Arsenic Monolayers Formed by Zero-Dimensional Tetrahedral Clusters and One-Dimensional Armchair Nanochains.

One-dimensional (1D) arsenene nanostructures are predicted to host a variety of interesting physical properties including antiferromagnetic, semiconductor-semimetal transition and quantum spin Hall effect, which thus holds great promise for next-generation electronic and spintronic devices. Herein, we devised a surface template strategy in a combination with surface-catalyzed decomposition of molecular As cluster toward the synthesis of the superlattice of ultranarrow armchair arsenic nanochains in a large domain on Au(111). In the low annealing temperature window, zero-dimensional As nanoclusters are assembled into continuous films through intermolecular van der Waals and molecule-substrate interactions.

Outer Valence Photoionization and Autoionization of Formaldehyde.

We investigate photoionization from the ground electronic state of the formaldehyde molecule. Both partial cross sections and asymmetry parameters leading to the , , , and states of HCO ions are studied in the photon region of 10-90 eV using a multichannel -matrix method, which uses the configuration interaction (CI) to describe electronic correlation. We check the sensitivity of the results to change descriptions of the continuum, the different partial waves, and the active spaces in the theoretical model.

Pressure-Tuned Intralayer Exchange in Superlattice-Like MnBiTe/(BiTe) Topological Insulators.

The magnetic structures of MnBiTe(BiTe) can be manipulated by tuning the interlayer coupling via the number of BiTe spacer layers , while the intralayer ferromagnetic (FM) exchange coupling is considered too robust to control. By applying hydrostatic pressure up to 3.5 GPa, we discover opposite responses of magnetic properties for = 1 and 2.

Electrochemically Exfoliated Platinum Dichalcogenide Atomic Layers for High-Performance Air-Stable Infrared Photodetectors.

Platinum dichalcogenide (PtX), an emergent group-10 transition metal dichalcogenide (TMD) has shown great potential in infrared photonic and optoelectronic applications due to its layer-dependent electronic structure with potentially suitable bandgap. However, a scalable synthesis of PtSe and PtTe atomic layers with controlled thickness still represents a major challenge in this field because of the strong interlayer interactions. Herein, we develop a facile cathodic exfoliation approach for the synthesis of solution-processable high-quality PtSe and PtTe atomic layers for high-performance infrared (IR) photodetection.

Superconductivity in a Hole-Doped Mott-Insulating Triangular Adatom Layer on a Silicon Surface.

Adsorption of one-third monolayer of Sn on an atomically clean Si(111) substrate produces a two-dimensional triangular adatom lattice with one unpaired electron per site. This dilute adatom reconstruction is an antiferromagnetic Mott insulator; however, the system can be modulation doped and metallized using heavily doped p-type Si(111) substrates. Here, we show that the hole-doped dilute adatom layer on a degenerately doped p-type Si(111) wafer is superconducting with a critical temperature of 4.

Symmetric Sodium-Ion Battery Based on Dual-Electron Reactions of NASICON-Structured NaMnTi(PO) Material.

Symmetric sodium-ion batteries possess promising features such as low cost, easy manufacturing process, and facile recycling post-process, which are suitable for the application of large-scale stationary energy storage. Herein, we proposed a symmetric sodium-ion battery based on dual-electron reactions of a NASICON-structured NaMnTi(PO) material. The NaMnTi(PO) electrode can deliver a stable capacity of up to 160 mAh g with a Coulombic efficiency of 97% at 0.

On-Surface Synthesis of Graphene Nanoribbons on Two-Dimensional Rare Earth-Gold Intermetallic Compounds.

Here, we demonstrate two reliable routes for the fabrication of armchair-edge graphene nanoribbons (GNRs) on TbAu/Au(111), belonging to a class of two-dimensional ferromagnetic rare earth-gold intermetallic compounds. On-surface synthesis directly on TbAu leads to the formation of GNRs, which are short and interconnected with each other. In contrast, the intercalation approach-on-surface synthesis of GNRs directly on Au(111) followed by rare earth intercalation-yields GNRs on TbAu/Au(111), where both the ribbons and TbAu are of high quality comparable with those directly grown on clean Au(111).

Synthesis of nanoporous graphenes via decarboxylation reaction.

Two kinds of C-C bonded crystalline nanoporous graphenes (NPGs) have been synthesized by using a newly developed decarboxylation reaction. Both NPGs show good electrocatalytic oxygen evolution reaction (OER) activities. The clear pore-edge structures of the synthesized NPGs provide an ideal platform for further OER investigations.

Two-Dimensional Rare Earth-Gold Intermetallic Compounds on Au(111) by Surface Alloying.

Surface alloying is a straightforward route to control and modify the structure and electronic properties of surfaces. Here, we present a systematic study on the structural and electronic properties of three novel rare earth-based intermetallic compounds, namely, ReAu (Re = Tb, Ho, and Er), on Au(111) via directly depositing rare earth metals onto the hot Au(111) surface. Scanning tunneling microscopy/spectroscopy measurements reveal very similar atomic structures and electronic properties, e.

Band Sharpening and Band Alignment Enable High Quality Factor to Enhance Thermoelectric Performance in -Type PbS.

Low-cost and earth-abundant PbS-based thermoelectrics are expected to be an alternative for PbTe, and have attracted extensive attentions from thermoelectric community. Herein, a maximum () ≈ 1.3 at 923 K in -type PbS is obtained through synergistically optimizing quality factor with Sn alloying and PbTe phase incorporation.

A two-dimensional ErCu intermetallic compound on Cu(111) with moiré-pattern-modulated electronic structures.

A rare-earth compound on a metal may form a two-dimensional (2D) intermetallic compound whose properties can be further modulated by the underlying substrate periodicity and coupling. Here, we present a combinational and systematic investigation using scanning tunneling microscopy/spectroscopy (STM/STS) and density functional theory (DFT) calculations on erbium (Er) on Cu(111). Experimentally, an intriguing growth mode transition from a branched island to a fractal-like island has been observed depending on whether the deposition process of Er is interrupted for a certain duration: post-deposition effects, such as nucleation and island growth controlled by diffusion, play an essential role in altering the Er island edge and its activity.

The shielding effects of a C cage on the magnetic moments of transition metal atoms inside the corner holes of Si(111)-(7 × 7).

The strong interaction between transition metal (TM) atoms and semiconductor surface atoms may diminish the magnetic moments of the TM atoms and prevent them from being used as single atom spin-based devices. A carbon cage that can encapsulate TM atoms and isolate them from interacting with surface atoms is considered to protect the magnetic moments of the TM atoms. We have studied the magnetic moments of Fe, Co, and Ni atoms adsorbed inside the corner hole of Si(111)-(7 × 7) by using first-principles calculations based on the density functional theory.

3D charge and 2D phonon transports leading to high out-of-plane in n-type SnSe crystals.

Thermoelectric technology enables the harvest of waste heat and its direct conversion into electricity. The conversion efficiency is determined by the materials figure of merit Here we show a maximum of ~2.8 ± 0.

MRCI study on transition dipole moments and transition probabilities of 18 low-lying states of CP cation.

This study calculates the potential energy curves of 18 Λ-S and 50 Ω states, which arise from the C(P) + P(P) dissociation channel of the CP cation. The calculations are made using the CASSCF method, followed by the icMRCI approach with the Davidson correction. Core-valence correlation and scalar relativistic corrections, as well as extrapolation to the complete basis set limit are included.

Growth Behavior of Pristine and Potassium Doped Coronene Thin Films on Substrates with Tuned Coupling Strength.

The growth of polycyclic aromatic hydrocarbon (PAH) molecular coronene film on various substrates and the subsequent doping of potassium under ultrahigh vacuum (UHV) conditions have been systematically investigated by low-temperature scanning tunneling microscopy and spectroscopy (STM/STS). The crystalline structures and molecular orientations of coronene thin films are both thickness-dependent and substrate-sensitive due to the competition between molecule-substrate interaction and intermolecular interaction. In mono- or bilayer films, coronene molecules are flat-lying on the surface with hexagonal lattice, whereas in multilayer films, the topmost molecules are in a standing-up but tilted configuration with rectangular lattice.

Controllable dissociations of PH3 molecules on Si(001).

We demonstrate for the first time to our knowledge that controllable dissociation of PH3 adsorption products PHx (x = 2, 1) can be realized by STM (scanning tunneling microscope) manipulation techniques at room temperature. Five dissociative products and their geometric structures are identified via combining STM experiments and first-principle calculations and simulations. In total we realize nine kinds of controllable dissociations by applying a voltage pulse among the PH3-related structures on Si(001).

Generalized Energy-Based Fragmentation CCSD(T)-F12a Method and Application to the Relative Energies of Water Clusters (H2O)20.

The generalized energy-based fragmentation (GEBF) approach has been implemented for the explicitly correlated F12a of coupled-cluster with the noniterative triples corrections [CCSD(T)-F12a] method for medium- and large-sized systems. By combining the canonical Hartree-Fock (HF) total energies and the GEBF-X correlation energies, the GEBF-X/HF method is illustrated to be more accurate than the origin GEBF-X method, where X could be any electron correlation method, such as second-order Møller-Plesset perturbation theory (MP2), MP2-F12, CCSD(T), and CCSD(T)-F12a. By combining the GEBF-X/HF results at the MP2-F12 and CCSD(T)-F12a levels, we can approximately achieve the CCSD(T) complete basis set (CBS) limit.