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2D half‐metallic multiferroic materials have attracted great interest due to their rich novel performances and wide application prospect in nanoelectronics and nanodevices. Three intrinsic half‐metallic multiferroic monolayers AV2S4 (A = Na, K, and Rb) are predicted based on the first‐principles calculations. From the calculations, their ground states are all ferromagnetic and are completely spin‐polarized at the Fermi level. Their total magnetic moments are always 3.00 μB per primitive cell, which origin mainly from V‐ions. The two‐center electronic structure t2g6↑t2g4↓eg1↑ of V‐ions is proposed from the perspective of the crystal field theory to explain successfully the calculated magnetic moments. Interestingly, the alkali‐metal ions are non‐magnetic, but they may cause important influence on the magnetic coupling between transition ions, and then the half‐metallicity of these monolayers. Their electric and magnetic properties may be tuned by their charge states and strains. Especially, their half‐metallic stability may be evidently improved by the tensile strains. The half‐metallic gaps of these monolayers may be increased by about 67.4%, 50.8%, and 32.4% for NaV2S4, KV2S4, and RbV2S4 by the tensile strain 2.0%, respectively. [ABSTRACT FROM AUTHOR]

Blockchain has been widely used to trace logistics information from sources to destinations in shipping logistics practices. Motivated by market practices, this study intends to discuss the potential application value of blockchain platforms in shipping logistics, considering the perceived utility of consumers. For this purpose, to investigate the shipping logistics supply chain (SLSC) of a shipping company (SC) and a freight forwarding company (FFC), in which FFC decides whether to introduce a blockchain platform and its introduction channel. Specifically, three channel models are considered: Model T (i.e., traditional logistics supply chain channel), Model B (i.e., FFCs applied a blockchain platform via a self-built platform channel), and Model J (i.e., FFCs applied a blockchain platform via joining a third-party platform channel). Meanwhile, the Nash and Stackelberg game are used to characterize the companies' equilibrium outcomes under different power structures. By comparing these three modes, some interesting results are found: consumer perception of the level of service and privacy protection and consumer sensitivity to price has critical effects on the value of blockchain platforms. Results also show that the blockchain platform does not always motivate the members of the SLSC to become better. Whether the power structure is symmetrical or asymmetrical, FFC adopts Model B instead of Model J, in which the blockchain platform can help FFC increase profits, and the value of blockchain is significant. Moreover, the FFC can obtain at least approximately 78% more benefit when the power structure is symmetrical than asymmetrical. However, the value of blockchain platforms to SC is not necessarily significant. The value of the blockchain platform for SC is significant only in Model B with the power structure asymmetric. Therefore, the value of the blockchain platform in Model B with the power structure asymmetrical for both FFCs and SCs is significant, achieving a win-win situation. Also, an extensive numerical analysis showing the optimal channel strategy in the three models generated additional management insights. [ABSTRACT FROM AUTHOR]

Half-metallic nanosheets are attracting increasing attention due to their advantages such as low power consumption, high storage density, non-volatile information in spintronics. Furthermore, the nanometer multiferroic materials exhibit new singular abundant physical capabilities and application potential. In this paper, several non-vdW multiferroic half-metallic nanosheets ACr2S4 (A = Li, Na, K and Rb) were predicted by the first-principles calculations. It was found that the geometric structures of these nanosheets are stable and their ground states are all ferromagnetic. The half-metallicity of these nanosheets is all stable within a certain biaxial stain range and their magnetic moments per unit always retain at 5.00 μB, which origin mainly from Cr-ions and partially from the S-ions. There is strong ferromagnetic coupling between Cr-ions and weak antiferromagnetic coupling between Cr-ions and S-ions. The half-metallicity of these nanosheets may be improved significantly by the biaxial tensile strain. Based on the crystal field theory, the two-center electronic structures t2g6↑t2g4↓eg3↑were built, which provides direct physical insights into the origin of the half-metallicity and the magnetic moment. [ABSTRACT FROM AUTHOR]