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Currently, two-dimensional (2D) ferromagnetic (FM) materials have become one type of promising spintronic devices. However, the practical applications of 2D FM materials are severely hampered by low Curie temperature (TC), which emphasizes the urgent need to design high-temperature 2D ferromagnets. Herein, we predict two stable Kagome-latticed Ti3X4 (X = S or Se) monolayers using first-principles calculations and investigate their stability, electronic structures, and magnetism. The Ti3S4 monolayer is a robust FM bipolar magnetic semiconductor with a band gap of 0.41 eV, and the Ti3Se4 monolayer is a FM half metal (HM) with a band gap in the spin-down channel of 0.44 eV. Monte Carlo simulations indicate that both Ti3S4 and Ti3Se4 monolayers exhibit above-room-temperature TCs of 382 and 436 K, respectively. Interestingly, the FM–antiferromagnetic transition and HM-to-semiconductor transition are found under tensile strains. Our findings propose an effective platform to design promising FM candidates for potential spintronic devices. [ABSTRACT FROM AUTHOR]

Currently, intercalation has become an effective way to modify the fundamental properties of two-dimensional (2D) van der Waals (vdW) materials. Using density functional theory, we systematically investigated the structures and electronic and magnetic properties of bilayer transition metal dichalcogenides (TMDs) intercalated with 3d TM atoms (TM = Sc–Ni), TM@BL_MS2 (M = Mo, V). Our results demonstrate that all the studied TM@BL_MS2s are of high stability, with large binding energies and high diffusion barriers of TM atoms. Interestingly, most TM@BL_MoS2s and TM@BL_VS2s are found to be stable ferromagnets. Among them, TM@BL_MoS2s (TM = Sc, Ti, Fe, Co) are ferromagnetic metals, TM@BL_MoS2 (TM = V, Cr) and TM@BL_VS2 (TM = Sc, V) are ferromagnetic half-metals, and the remaining systems are found to be ferromagnetic semiconductors. Exceptions are found for Ni@BL_MoS2 and Cr@BL_VS2, which are nonmagnetic semiconductors and ferrimagnetic half-metals, respectively. Further investigations reveal that the electromagnetic properties of TM@BL_MoS2 are significantly influenced by the concentration of intercalated TM atoms. Our study demonstrates that TM atom intercalation is an effective approach for manipulating the electromagnetic properties of two-dimensional materials, facilitating their potential applications in spintronic devices. [ABSTRACT FROM AUTHOR]

The impact of the intercropping system on the soil–plant–atmosphere continuum (SPAC), encompassing soil evaporation, soil moisture dynamics, and crop transpiration, remains an area of uncertainty. Field experiments were conducted for two years in conjunction with the SIMDualKc (Simulation Dual Crop Coefficient) model to simulate two planting configurations: sole-cropped wolfberry (Lycium barbarum L.) (D) and wolfberry intercropped with alfalfa (Medicago sativa L.) (J). These configurations were subjected to different irrigation levels: full irrigation (W1, 75–85% θfc), mild deficit irrigation (W2, 65–75% θfc), moderate deficit irrigation (W3, 55–65% θfc), and severe deficit irrigation (W4, 45–55% θfc). The findings revealed that the JW1 treatment reduced the annual average soil evaporation by 32% compared with that of DW1. Additionally, mild, moderate, and severe deficit irrigation reduced soil evaporation by 17, 24, and 36%, respectively, compared with full irrigation. The intercropping system exhibited a more efficient canopy structure, resulting in reduced soil evaporation and alleviation of water stress to a certain extent. In terms of temporal dynamics, monocropping resulted in soil moisture levels from 1% to 15% higher than intercropping, with the most significant differences manifesting in the mid to late stages, whereas differences in the early stages were not statistically significant. Spatially, the intercropping system exhibited 7–19% lower soil water contents (SWCs) than sole cropping, primarily within the root water uptake zone within the 0–60 cm soil layer. The intercropping system showed an enhanced water absorption capacity for plant transpiration, resulting in a 29% increase in transpiration compared with sole cropping, thereby achieving water-saving benefits. These findings contribute to our understanding of the agronomic and environmental implications of intercropping wolfberry and alfalfa in arid regions and provide insights into optimizing water and soil resource management for sustainable agricultural practices. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) ferromagnetic semiconductors (FM SCs) provide an ideal platform for the development of quantum information technology in nanoscale devices. However, many developed 2D FM materials present a very low Curie temperature (TC), greatly limiting their application in spintronic devices. In this work, we predict two stable 2D transition metal chalcogenides, V3Se3X2 (X = S, Te) monolayers, by using first-principles calculations. Our results show that the V3Se3Te2 monolayer is a robust bipolar magnetic SC with a moderate bandgap of 0.53 eV, while V3Se3S2 is a direct band-gap FM SC with a bandgap of 0.59 eV. Interestingly, the ferromagnetisms of both monolayers are robust due to the V–S/Se/Te–V superexchange interaction, and TCs are about 406 K and 301 K, respectively. Applying biaxial strains, the FM SC to antiferromagnetic (AFM) SC transition is revealed at 5% and 3% of biaxial tensile strain. In addition, their high mechanical, dynamical, and thermal stabilities are further verified by phonon dispersion calculations and ab initio molecular dynamics (AIMD) calculations. Their outstanding attributes render the V3Se3Y2 (Y = S, Te) monolayers promising candidates as 2D FM SCs for a wide range of applications. [ABSTRACT FROM AUTHOR]

Borophene with rich polymorphs has largely enriched the family of two-dimensional materials and attracted great research interest. Recently, the evolution of bilayer borophene (BLB) structures has aroused curiosity about the exploration of more members of BLB and their stability mechanism. Herein, we predicted a number of stable BLBs built by borophene monolayers using density functional theory calculations. Interestingly, four BLB polymorphs, such as α5-BLB, β8-BLB, α4-BLB, and β9-BLB, are identified as semiconductors with band gaps of 0.81, 0.34, 0.04, and 0.02 eV, respectively. In addition, four other types of BLBs, i.e., α3-BLB, β1-BLB, β6-BLB, and β12-BLB, are found to be stable metals. It is revealed that the interlayer B–B pillars play a crucial role in balancing the distribution of surplus electronic density in BLBs and are responsible for their super stabilities than those of borophene monolayers. Besides, the strong interlayer covalent interaction plays an important role in the semiconducting properties of these BLBs. Our results are helpful to understand the stability mechanism of BLB structures and expand the family of bilayer borophenes. [ABSTRACT FROM AUTHOR]

In this paper, site preference, phase stability and elastic parameters of MoSi2 for Al and Nb addition are studied using first-principles calculation. The results show that alloying elements can cause MoSi2 to change from C11b to C40 phase and the phase transition is due to the activated 1/2[ 1 ̄ 11](110) slip system for C11b. G ∕ B ratio reveals that the ductility is enhanced after phase transition. Ductile factor σ γ m ∕ σ c based on competitive processes between micro-crack opening and dislocations emission is defined to assess the ductility of MoSi2. Interestingly, the increased ductility is due to the activated dislocation emission but suppressed crack propagation. Finally, charge density and DOS indicate that the improved ductility is due to the weakened Mo-4d and Si-3p covalent interactions. [ABSTRACT FROM AUTHOR]