Thermal management in two-dimensional (2D) materials is pivotal, given their extensive technological utility in miniaturized devices. However, an expedient yet precise method for predicting the thermal transport properties of 2D materials remains to be established. In this study, we derive analytical formulas for calculating the scattering rate of three-phonon Umklapp processes, specifically tailored to 2D materials, based on the continuous elasticity assumption, quasi-harmonic approximation, and central force approximation. These formulas enable the construction of a refined Debye-Callaway model that incorporates the effects of both three-phonon Umklapp scattering and boundary scattering, eliminating the need for any fitting parameters. Notably, we explicitly disentangle the contributions of optical phonons, treating them within a framework analogous to the Einstein model. This improved model facilitates efficient and accurate predictions of the anisotropic lattice thermal conductivities in 2D materials. The results generated by our model for 12 2D crystals show excellent agreement with those from fully first-principles calculations reported in the literature. In particular, this study clarifies how the relaxation time fitting parameter adopted in previous work depends on the crystal structure and dimensional characteristics of the materials. It also provides an understanding of the logarithmic divergence of lattice thermal conductivity with respect to the size of 2D crystals within a framework involving only three-phonon scattering processes and Debye approximation. Owing to its low computational cost and high prediction precision, this model can serve as a valuable tool for high-throughput screening and machine learning applications in the identification of 2D materials with tailored thermal conductivity.

Chemical mechanical polishing (CMP) traditionally relies on a synergistic interplay between mechanical abrasion and chemical etching, yet the limited chemical activity of conventional abrasives often restricts efficiency. Herein, a photoassisted in situ Ce3+ enrichment strategy is established and applied in a core-shell abrasive with Ce-doped SnO2 (CTO) as core and La-doped CeO2 (LCO) as shell (CTO@LCO). A type-II heterojunction at the core-shell interface facilitates efficient photogenerated electron transfer from CTO to LCO, highly promoting the chemical activity of the LCO shell. Combined with the robust mechanical action of faceted CTO core, the CTO@LCO abrasive exhibits remarkable material removal rate (MRR) of 608 nm/min for TFT-LCD glass and 315 nm/min for Si wafer, and simultaneously reduced surface roughness (Ra) of 0.277 and 0.190 nm, respectively, outperforming commercial CeO2 abrasives by 129.56% (137.84%) in MRR and 45.02% (61.83%) in Ra. Comprehensive experimental characterizations and first-principles calculations shed light on the mechanism of doping-induced band structure regulation and heterointerface design in such photoassisted chemical mechanical polishing (PACMP). This work opens a way to in situ chemically activate abrasives for high-performance CMP toward advanced ultraprecision manufacturing.

PbHg3Ti4O12 (PHTO) represents the first example of ferroelectricity in quadruple A-site-ordered perovskites AA'3B4O12, which features Hg2+ ions in an unusual 8-fold coordination at the A'-site, forming a structural bridge between simple perovskites and conventional A-site-ordered perovskites. Here, we engineer the A-site charge and lone-pair activity by substituting La3+ for Pb2+, and synthesize a new A-site-ordered perovskite LaHg3Ti4O12+δ (LHTO) under high-pressure and high-temperature conditions. LHTO crystallizes in the centrosymmetric Im3̅ structure at room temperature and is isostructural with PHTO, retaining the 8-fold coordination of the Hg2+ ions. Structural and dielectric characterizations, and first-principles calculations, show a structural instability around 90 K driven by phonon soft modes dominated by Ti-O vibration and the weakening of lone pair, which prevents the development of long-range ferroelectric order. Our results establish a dual A-site design strategy─tuning both lone-pair activity and electron doping─for controlling ferroelectricity in A-site-ordered quadruple perovskites and uncover a competing instability characteristic of this intermediate-coordination regime.

The development of efficient photocatalysts is crucial for addressing the energy crisis and environmental pollution. However, the charge transfer mechanisms in polar materials along with the influence of external electric fields are still unclear. Herein, this research explores the dipole moments and carrier dynamics in Janus SnSSe/MoSi2N4 heterojunctions by first-principles calculations and nonadiabatic molecular dynamics simulations. Our results show that the S/N configuration has a dipole moment of 0.03 eÅ, and the Se/N configuration exhibits a much larger dipole moment of 0.18 eÅ. Both configurations follow an S-scheme charge-transfer mechanism, with interfacial electron-hole recombination times as short as 11 ps (S/N) and 25.13 ps (Se/N), which are substantially faster than the intralayer electron and hole transfer times. The application of an external electric field influences the electronic properties and polarity of the heterojunction. Moreover, a positive electric field further strengthens the S-scheme charge-transfer character. The S/N contact configuration demonstrates superior photocatalytic performance compared to the Se/N configuration and individual monolayers, exhibiting promising reaction activity. This letter provides deep insights and theoretical guidance for designing novel S-scheme heterojunctions with tunable photocatalytic properties.

The interplay of topology and chirality in non-symmorphic chiral crystals unveils novel quantum phenomena such as chiral anomalies and exotic fermionic excitations with extended Fermi arcs. In this study, we unify two seemingly distinct concepts topological phonons, arising from non-trivial band topology, and chiral phonons, associated with circular polarization and non-zero angular momentum through the lens of Weyl phonons in chiral CoGe phase. Using first-principles calculations, symmetry analysis, and effective modeling, we reveal the entanglement of chiral and topological phonons in the P 2 1 3 phase of CoGe. We show that crystal chirality dictates topological charge, mirror enantiomers host Weyl phonons with opposite charges, distinct surface states, and reversed arc connections. Remarkably, we identify quadruple two-fold degenerate Weyl nodes with a Chern number of ±4 the highest reported for phononic systems. Due to the C 3 rotational symmetry along the Γ-R direction, chiral phonon modes emerge naturally, with circular polarization reversing under mirror operations mirroring the topological charge reversal.We propose helicity-resolved Raman spectroscopy as a powerful tool to detect these chiral phonons, linking circular polarization to Berry curvature and phonon angular momentum.Additionally, we explore a distorted kagome lattice phase (space group P-62m) of CoGe, predicting Dirac nodal lines and triply degenerate phonon points. In this achiral structure, valley-selective chiral phonons emerge at ±K(±H) points, exhibiting opposite circular polarization. Our findings establish CoGe as a versatile platform to explore a wide range of phononic topological quasiparticles, including spin-1/2 Weyl, spin-1 Weyl, charge-2 Dirac, charge-4 Weyl, Dirac nodal lines,type-I and type-III quadratic nodal points, and triply degenerate nodal points.

In his groundbreaking work on the theory of ferri- and antiferromagnetism, Néel proposed the existence of ferrimagnets with zero net magnetization. These L -type ferrimagnets were later termed fully compensated. This study focuses on L -type ferrimagnets, particularly Heusler alloys based on vanadium (V), manganese (Mn), iron (Fe), and cobalt (Co). First-principles calculations reveal that these ferrimagnets exhibit anomalous temperature dependence, differing from antiferromagnets. Spin dynamics calculations, based on the calculated exchange coupling coefficients, show that this behavior stems from the ferrimagnets' inequivalent magnetic sublattices, which have distinct exchange interactions. The temperature dependence of the magnetic properties is analyzed through a comparison of the first-principles calculations and Néel's molecular field theory, extended to include Heusler compounds. In addition to exhibiting compensated ferrimagnetic behavior, examining the electronic structure using the Bloch spectral function shows that the investigated Heusler alloys are half-metals which have a full spin polarization at the Fermi energy. The combination of complete magnetic compensation and half-metallicity makes these alloys interesting for fundamental research and spintronics applications because their zero net magnetization minimizes stray fields while retaining half-metallicity.

Coal slime water treatment and resource recovery are vital for the sustainable development of coal industry sustainability. Kaolinite, over 60% of clay minerals in coal slime water, is key for high-value flotation utilization. Phosphonic-acid collectors adsorb effectively on kaolinite via -PO(OH)2 groups, but their structural diversity (phenyl/benzylphosphonic acids and esters) blurs structure-adsorption relationships. Existing studies focus on single collectors for specific minerals, lack a systematic screening/prediction database, and rarely combine first-principle calculations with three-dimensional quantitative structure-activity relationship (3D-QSAR) to explore multi-type collector mechanisms on kaolinite. This study combined density functional theory (DFT) with 3D-QSAR to study phosphonic-acid collector adsorption on kaolinite (001). Comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) models were validated, with CoMSIA performing optimally (q2 = 0.843, r2 = 0.984). Diethyl (2-chlorobenzyl)phosphonate and (2-hydroxyphenyl)phosphonic acid in the test set showed prediction errors < 1%, confirming reliability. Two novel collectors (4-propylphenylphosphonic acid, 3-methyl-4-nitrophenylphosphonic acid) were designed, outperforming all database collectors, corroborating model validity and supporting high-efficiency collector development for kaolinite recovery. First-principle calculations via Cambridge Serial Total Energy Package (CASTEP) yielded the adsorption energies of 35 phenyl/benzylphosphonic acids/esters on kaolinite (001) to build a molecular structure-adsorption database. The dataset was split into 80% training and 20% test sets post molecular energy minimization. CoMFA/CoMSIA models were built via partial least squares (PLS) regression, evaluated by q2, r2, F-statistic and standard error of estimate (SEE); contour maps analyzed molecular field effects. New collectors were designed via CoMSIA and DFT-verified.

We systematically investigate the impact of ordered configurations of group III atoms on the formation enthalpy of zinc blende III–V alloys using first-principles calculations. The study focuses on 12 quasibinary systems: AlxGa1−xN, AlxIn1−xN, GaxIn1−xN, AlxGa1−xP, AlxIn1−xP, GaxIn1−xP, AlxGa1−xAs, AlxIn1−xAs, GaxIn1−xAs, AlxGa1−xSb, AlxIn1−xSb, and GaxIn1−xSb. Since the spatial distribution of group III cations in the zinc blende structure is equivalent to that in a face-centered cubic (FCC) lattice, FCC-based ordered phases are employed to compare formation enthalpies across different configurations. For compositions of x = 0.25 and 0.75, we compare the formation enthalpies of three ordered structures—L12, D023, and D022—with those of a random solid solution (RSS), in which group III elements are randomly distributed. At x = 0.5, four ordered structures—L10, L11, Y2, and chalcopyrite—are evaluated in comparison with the RSS structure. Our results reveal that for AlxGa1−xP, AlxGa1−xAs, and AlxGa1−xSb at x = 0.25 and 0.75, the RSS structure exhibits the lowest formation enthalpy, indicating a thermodynamic preference for disordered configurations. In contrast, at x = 0.5, the L11 structure is the most stable for these systems. For the remaining quasibinary systems, the D022 and chalcopyrite structures are energetically favored. However, all minimum formation enthalpies remain positive, suggesting that the ordered phases are thermodynamically metastable across the studied compositions. These findings offer fundamental insights into the relationship between atomistic ordering and formation enthalpy in III–V alloys, thereby providing a theoretical basis for predictive modeling and guiding future experimental efforts in materials design.

Colloidal quantum dots (CQDs) based on II-V semiconductors offer attractive optical absorption and carrier transport properties for infrared optoelectronics, yet their device-relevant electronic behavior remains poorly understood. In particular, Cd3P2 CQDs have been constrained by limited control over nanocrystal growth and carrier polarity. Here, a materials-to-device study establishes polarity control in Cd3P2 CQD solids for infrared photodiodes. Precise regulation of oleic acid (OA) concentration during synthesis yields monodisperse Cd3P2 CQDs with suppressed nanocrystal fusion and photoluminescence quantum yields up to 62 %. Electrical measurements reveal an oxygen-induced transition from n-type to p-type transport in Cd3P2 CQD films. Spectroscopic analysis and first-principles calculations indicate that adsorbed oxygen generates surface acceptor states that drive Fermi-level realignment. Building on these functional Cd3P2 CQD solids, a Cd3P2-based homojunction CQD photodiode is demonstrated, in which Cd3P2 functions as both the infrared absorber and a charge-selective layer. The resulting devices exhibit stable ambient operation, achieving a short-circuit current density of 18mA cm-2, an external quantum efficiency (EQE) of 24 %, and a fast temporal response of 23ns under zero bias. These results identify surface-driven polarity control as a viable design strategy for II-V CQD optoelectronics and position Cd3P2 CQDs as a promising platform for low-power infrared conversion technologies.

Precise structural design is vital for advancing high-performance birefringent crystals used in mid-infrared polarizing devices. Mixed anion systems, particularly chalcohalides, present a promising avenue by synergistically combining the broad infrared transparency of chalcogenides with the band gap-widening capability conferred by halide ions. Guided by this approach, a novel chalcohalide birefringent crystal, Ba4CdGa2S6F4, was successfully designed and synthesized by the cation and anion cosubstitution strategy. This compound was derived from the parent phase Ba5Ga2S8 by partially replacing one Ba2+ cation with one Cd2+ cation and two S2- anions with four F- anions. Optical characterization via the UV-vis-NIR diffuse reflectance measurement reveals that Ba4CdGa2S6F4 exhibits a large optical band gap of 3.78 eV. And the broad infrared transparency of Ba4CdGa2S6F4 is confirmed for the material via both Raman and Fourier transform IR spectroscopy. First-principles calculations indicate that Ba4CdGa2S6F4 has moderate birefringence with a value of 0.057 at 1064 nm, representing a 26.6% increase over the parent compound Ba5Ga2S8. This work not only reports a promising infrared birefringent crystal with large band gap but also demonstrates that the cation and anion cosubstitution is an effective strategy for designing novel functional crystalline materials.

ABSTRACT Chloride-based Li2FeCl4 has emerged as a promising candidate high-voltage, highly deformable cathode material for all-solid-state lithium-ion batteries. However, further enhancement of Li-ion conductivity is required for practical application. In this study, we synthesized Br-substituted Li2FeCl3.8Br0.2 and examined how partial anion substitution influences both the crystal structure and Li-ion conductivity. X-ray diffraction confirmed that a single-phase cubic framework was retained and that the lattice constant remained unchanged despite Br incorporation. As a result of AC impedance measurements, the ionic conductivity was confirmed to increase approximately twofold, from 2.0 × 10−5 S/cm for the pristine material to 4.0 × 10−5 S/cm for the Br-substituted sample. In an effort to uncover the underlying mechanism of this enhancement, first-principles calculations (Density Functional Theory) combined with genetic algorithm – driven structural optimization were performed. The calculations indicated that Br substitution promoted a more disordered occupancy of Li ions across the sites along the conduction pathways. These results demonstrate that targeted anion substitution effectively tunes the Li-site energy landscape and controls Li-ion conductivity in chloride cathode materials.

Synergistic effects of Re and C/O on grain boundary strength in Mo by first-principles calculation

Research on strain-responsive Arsenene/SnSeS heterojunction for digital media technology: A first-principles calculations

Investigation on mechanical properties of the Ti3AlC2/TiC interface: First-principles calculations

First-principles calculations on the electronic structure of Co-doped diamond

First-principles calculations and high-temperature performance of laser cladding AlCoCrFeNiNbxSi1-x HEA coatings

Thermodynamic reassessment of Mg-Sn-Y system assisted by the first-principles calculations and key experiments

Monolayer and bilayer Dodeca-carbon as high-performance anode materials for sodium- and potassium-ion batteries: Insights from first-principles calculations

Fe- and Li-decorated hydrogen boride as a gas sensor for CO, NO, and CO2 detection: A DFT study.

Elucidating the electron-driven mechanism of H2O dissociation on Pt nanoclusters via modulating the doped graphene substrate and applied electrode potential.