First-principles Calculations Research Articles

Predicting and understanding vacancy-modified oxygen diffusion in dilute Ni-based alloys by first-principles calculations

Predicting and understanding vacancy-modified oxygen diffusion in dilute Ni-based alloys by first-principles calculations

High-entropy layered cathode structures and their properties based on first-principles calculations

High-entropy layered cathode structures and their properties based on first-principles calculations

Hydrogen diffusion in yttrium hydrides: First-principles calculations and machine learning molecular dynamics

Hydrogen diffusion in yttrium hydrides: First-principles calculations and machine learning molecular dynamics

Optimization of β-Ga2O3 photocathode performance based on first-principles calculations

Optimization of β-Ga2O3 photocathode performance based on first-principles calculations

Novel superhard semiconductor carbon allotrope Pcc2 C24 under pressure: First-principles calculation

Novel superhard semiconductor carbon allotrope Pcc2 C24 under pressure: First-principles calculation

Exploring the pressure effect on structural, elastic and thermodynamic properties of transition metal carbides using first-principles calculations

Exploring the pressure effect on structural, elastic and thermodynamic properties of transition metal carbides using first-principles calculations

First-principles calculations on structural stability and electronic properties of the Strontium-Argon System at High Pressure

First-principles calculations on structural stability and electronic properties of the Strontium-Argon System at High Pressure

Multi-valley band and low thermal conductivity in two-dimensional Mg3Bi2 mono layer: A method for improving thermoelectric performance of Mg3Bi2 based on First-principles calculations

Multi-valley band and low thermal conductivity in two-dimensional Mg3Bi2 mono layer: A method for improving thermoelectric performance of Mg3Bi2 based on First-principles calculations

Elastic properties, fracture toughness, electronic properties and thermal conductivity of In-doped η'-Cu6Sn5 in Sn-Cu solders using first-principles calculations

Elastic properties, fracture toughness, electronic properties and thermal conductivity of In-doped η'-Cu6Sn5 in Sn-Cu solders using first-principles calculations

Electronic structure, lattice dynamics and superconductivity of CaPtSi polymorphs using first-principles calculations

Electronic structure, lattice dynamics and superconductivity of CaPtSi polymorphs using first-principles calculations

Reliable and high-performance Ag-doped MoSi2 film with enhanced mechanical and tribological properties

The Mo-Ag-Si solid solution film was prepared using magnetron sputtering to enhance hardness and toughness while reducing friction and wear. Compared with the pure MoSi2 film, the Mo-Ag-Si solid solution film exhibited a 25.69% increase in hardness, a 5.17% increase in the H/E ratio, and a 33.33% boost in the H³/E² ratio. Tribological tests revealed that Ag atoms formed a self-lubricating AgMoxOy phase, reducing the friction coefficient to 0.09 and the wear rate to 3.89 × 10⁻⁷ mm³/N·m over 565m. First-principle calculations indicate that the Mo-Ag-Si solid solution film exhibited better mechanical and tribological properties than the pure MoSi2 film. These findings provide another approach for developing reliable MoSi2 films with high performance.

The resistivity of rare earth impurities diluted in Lanthanum, Part I

We study the temperature-independent resistivity of rare-earth magnetic impurities (Gd, Tb, Dy) and the non-magnetic impurity (Lu) diluted in double hexagonal close-packed (dhcp) lanthanum. We model the system as a two-band system, where s-electrons perform conduction while d-electrons entirely screen the charge differences induced by impurities. Using the T-matrix formalism derived from the Dyson equation, we obtain an expression for resistivity. Since electronic properties are highly sensitive to band structure, we examine two types: a simplified “parabolic” band structure and a more realistic one obtained through first-principles calculations using VASP. Our results indicate that the exchange parameters, represented as cross products, significantly influence the magnitude of the spin resistivity term. Furthermore, we find that the role of band structure in resonant scattering and the formation of virtual bound states depends on the specific band structure employed. Additionally, our study addresses the effects of translational symmetry breaking and the excess charge introduced by rare-earth impurities on resistivity.

First-principles, magnetothermal and magnetocaloric calculations on Gd1-xCexMn2Ge2 ([formula omitted])

In this research, we study the two compounds, Gd0.5Ce0.5Mn2Ge2 and Gd0.33Ce0.67Mn2Ge2, employing the molecular field theory and the first-principles calculations. The electronic and elastic characteristics are determined through the use of Density Functional Theory (DFT) calculations. Super-cell DFT computations are utilized to calculate the overall density of states (DOS), elastic stiffness constants Cij, and various elastic properties e.g. bulk and shear moduli. The primary objective is to investigate important physical properties such as magnetization, magnetic heat capacity, and key aspects of the magnetocaloric effect including both isothermal magnetic entropy change ΔSm and adiabatic temperature change ΔTad., relative cooling power (RCP), and magnetic phase transition. We investigate these characteristics in magnetic fields up to 6 T and at temperatures up to 400 K. The two compounds show a Curie temperature TC around 340 K. We also studied the effect of high magnetic fields on the nature of the phase transition.

First-principles calculation of two metastable superhard carbon nanotube polymers: CNP-oC36，CNP-oC40

First-principles calculation of two metastable superhard carbon nanotube polymers: CNP-oC36，CNP-oC40

Enhancing MXene-Based anodes with two-dimensional VO2/V2CO2 heterostructures: A first-principles calculations study

Enhancing MXene-Based anodes with two-dimensional VO2/V2CO2 heterostructures: A first-principles calculations study

Molecular and Electronic Structures at Electrochemical Interfaces from In Situ Resonant X-Ray Diffraction.

An original approach to characterize electrochemical interfaces at the atomic level, a challenging topic toward the understanding of electrochemical reactivity, is reported. We employed in situ surface resonant X-ray diffraction experiments combined with their simulation using first-principle density functional theory calculations and were thus able to determine the molecular and electronic structures of the partially ionic layer facing the electrode surface, as well as the charge distribution in the surface metal layers. Pt(111) in an acidic medium at an applied potential excluding specific adsorption was studied. The presence of a positively charged counter layer composed of 1.60 water and 0.15 hydronium molecules per platinum surface unit cell at 2.8 Å from the oppositely charged Pt(111) surface was found. Our results give a unique insight into the water-metal interaction at the electrochemical interfaces.

SPACIER: on-demand polymer design with fully automated all-atom classical molecular dynamics integrated into machine learning pipelines

Machine learning has rapidly advanced the design and discovery of new materials with targeted applications in various systems. First-principles calculations and other computer experiments have been integrated into material design pipelines to address the lack of experimental data and the limitations of interpolative machine learning predictors. However, the enormous computational costs and technical challenges of automating computer experiments for polymeric materials have limited the availability of open-source automated polymer design systems that integrate molecular simulations and machine learning. We developed SPACIER, an open-source software program that incorporates RadonPy, a Python library for fully automated polymer physical property calculations based on all-atom classical molecular dynamics, into a Bayesian optimization-based polymer design system to overcome these challenges. As a proof-of-concept study, we synthesized optical polymers that surpass the Pareto boundary formed by the tradeoff between the refractive index and the Abbe number.

Selective Adsorption of CO2 over N2 on Graphene: Insights from First-Principles Calculations

Selective Adsorption of CO₂ over N₂ on Graphene: Insights from First-Principles Calculations

Pressure induced semimetal-to-metal transition and new structure of Ta2NiSe5 above 10 GPa

Previous studies of the transition metal chalcogenide Ta2NiSe5has identified two phase transitions occurring between 0-10 GPa, involving the excitonic insulator-to-semiconductor transition at 1 GPa and the semiconductor-to-semimetal transition at 3 GPa. However, there is still a lack of in-depth research on the changes in its physical properties changes above 10 GPa. In this study, Ta2NiSe5were investigated under high-pressure conditions using high-pressure x-ray diffraction and high-pressure x-ray absorption experiments. During the experimental process, a novel phase transition from the semimetal to the metal phase was observed between 10-60 GPa, specifically between 10-14 GPa, and the structure of the new phase was determined to be P21/m through first-principles calculations. This transition mechanism is attributed to the sliding of the weakly coupled layers of Ta2NiSe5within thea-cplane, leading to changes in the crystal lattice constants and symmetry. This research fills a gap in the understanding of Ta2NiSe5's crystal structure under high pressure and contributes to the broader field of transition metal chalcogenides.

Machine Learning Interatomic Potential for Modeling the Mechanical and Thermal Properties of Naphthyl-Based Nanotubes.

Two-dimensional (2D) nanomaterials are at the forefront of potential technological advancements. Carbon-based materials have been extensively studied since synthesizing graphene, which revealed properties of great interest for novel applications across diverse scientific and technological domains. New carbon allotropes continue to be explored theoretically, with several successful synthesis processes for carbon-based materials recently achieved. In this context, this study investigates the mechanical and thermal properties of DHQ-based monolayers and nanotubes, a carbon allotrope characterized by 4-, 6-, and 10-membered carbon rings, with a potential synthesis route using naphthalene as a molecular precursor. A machine-learned interatomic potential (MLIP) was developed to explore this nanomaterial's mechanical and thermal behavior at larger scales than those accessible through the first-principles calculations. The MLIP was trained on data derived from the DFT/PBE (density functional theory/Perdew-Burke-Ernzerhof) level using ab initio molecular dynamics (AIMD). Classical molecular dynamics (CMD) simulations, employing the trained MLIP, revealed that Young's modulus of DHQ-based nanotubes ranges from 127 to 243 N/m, depending on chirality and diameter, with fracture occurring at strains between 13.6 and 17.4% of the initial length. Regarding thermal response, a critical temperature of 2200 K was identified, marking the onset of a transition to an amorphous phase at higher temperatures.