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Two-dimensional (2D) polarized heterostructures with internal electric fields are potential photocatalysts for high catalytic performance. The Blue P/SiS van der Waals heterostructures were formed from monolayer Blue P and polar monolayer SiS with different stacking interfaces, including Si-P and P-S interfaces. The structural, electronic, optical and photocatalytic properties of the Blue P/SiS heterostructures were studied via first-principle calculations. The results showed that the Si-P-2 or P-S-4 stacking order contributes to the most stable heterostructure with the Si-P or P-S interface. The direction of the internal electric field is from the 001 surface toward the 00 1 ¯ surface, which is helpful for separating photo-generated electron–hole pairs. The bandgap and electrostatic potential differences in the Si-P-2(P-S-4) heterostructures are 1.74 eV (2.30 eV) and 0.287 eV (0.181 eV), respectively. Moreover, the Si-P-2(P-S-4) heterostructures possess suitable band alignment and wide ultraviolet and visible light spectrum regions. All results suggest that 2D polarized Blue P/SiS heterostructures are potential novel photocatalysts for water splitting under a wide ultraviolet and visible light spectrum region. [ABSTRACT FROM AUTHOR]

In this work, the effects of cerium doping and oxygen defects of ferroelectric Hf0.5Zr0.5O2 (HZO) are systematically studied by first-principles calculations. According to the results, the combined effect of Ce atoms and oxygen vacancy has a significant effect on the improvement of the orthorhombic phase fraction in HZO, and the mechanism of this phenomenon is also studied. The optimal concentration of Ce doping is 9.375 formula unit%, and the optimal concentration of oxygen vacancy is 9.375 formula unit%. The interaction between Ce doping and oxygen defects is also discussed from the perspective of structural stability and electrical balance. These findings are helpful for the preparation of Ce-doped HZO ferroelectric thin films and provide experience for the study of other dopants. [ABSTRACT FROM AUTHOR]

The content of iron oxides has a large impact on the properties of magnesium refractories, knowledge about the thermodynamic equilibria of the FeO–Fe2O3–MgO system is important for the design of refractory materials and resource utilization of solid wastes. The phase equilibria and thermodynamic data of the FeO–Fe2O3–MgO system have been critically evaluated and re‐optimized using the CALPHAD method. The ionic two‐sublattice model (Fe+2, Mg+2)P(O−2, Va, FeO1.5)Q was used to describe the liquid phase. A set of self‐consistent thermodynamic model parameters is presented to describe the phase equilibrium of the FeO–Fe2O3–MgO system. The calculated phase diagrams and thermodynamic properties, employing the optimized model parameters, exhibit excellent agreement with the experimental data. Moreover, the results demonstrate improved consistency when extrapolated to the multicomponent system, such as CaO–MgO–FeO–Fe2O3 and SiO2–MgO–FeO–Fe2O3 systems. The present thermodynamic modeling is useful to construct multicomponent oxide thermodynamic database and to guide the utilization of solid waste resources. [ABSTRACT FROM AUTHOR]

In this work, the effect of co-doping lanthanide and VB group elements on the phase fraction of HfO2 is studied by first-principles calculations. A significant increase in the ferroelectric orthorhombic phase fraction can be achieved by doping La with Ta or Nb, which would enhance the ferroelectricity of HfO2. Furthermore, during the screening process, it is observed that oxygen vacancies coupled with dopants can promote the formation of the ferroelectric phase in HfO2. These studies and results provide valuable methods for improving the ferroelectric properties of HfO2. [ABSTRACT FROM AUTHOR]

Interatomic potentials play a crucial role in the molecular dynamics (MD) simulation of silicon carbide (SiC). However, the ability of interatomic potentials to accurately describe certain physical properties of SiC has yet to be confirmed, particularly for hexagonal SiC. In this study, the mechanical, thermal, and defect properties of four SiC structures (3C-, 2H-, 4H-, and 6H-SiC) have been calculated with multiple interatomic potentials using the MD method, and then compared with the results obtained from density functional theory and experiments to assess the descriptive capabilities of these interatomic potentials. The results indicate that the T05 potential is suitable for describing the elastic constant and modulus of SiC. Thermal calculations show that the Vashishta, environment-dependent interatomic potential (EDIP), and modified embedded atom method (MEAM) potentials effectively describe the vibrational properties of SiC, and the T90 potential provides a better description of the thermal conductivity of SiC. The EDIP potential has a significant advantage in describing point defect formation energy in hexagonal SiC, and the GW potential is suitable for describing vacancy migration in hexagonal SiC. Furthermore, the T90 and T94 potentials can effectively predict the surface energies of the three low-index surfaces of 3C-SiC, and the Vashishta potential exhibits excellent capabilities in describing stacking fault properties in SiC. This work will be helpful for selecting a potential for SiC simulations. [ABSTRACT FROM AUTHOR]

In this work, the effect of VB metal doping HfO2 is studied by first-principles calculation. The doping of VB group elements has special oxygen defect behavior due to its pentavalent properties. Moreover, a metal co-doping method based on electronic compensation is explored to regulate oxygen defects in the ferroelectric phase. The influence of co-doping on ferroelectric polarization is also studied, and the results show that Sc-Nb and Sc-Ta co-doping are effective methods to improve the ferroelectricity of HfO2. These studies provide a potential method for regulation of oxygen defects and the improvement of ferroelectricity in HfO2-based ferroelectric thin films. [ABSTRACT FROM AUTHOR]