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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]

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]

MXenes have caused much attention due to their unique crystal characteristics, high strength and flexibility, and then wide applications in sensors, electrode materials, and nano-electronics in recent years. In this paper, a promising intrinsic bimetallic half-metallic MXene nanosheet Sc2Li2N3 was predicted based on the first-principles study. It is shown that the half-metallicity of this nanosheet is stable within a certain biaxial stain range and its magnetic moments per unit cell are always 1.00 μB. The half-metallic properties and magnetic moments of the nanosheet are mainly contributed by the non-metallic N-ions, which is different from other half-metallic MXene nanosheets whose half-metallicity origins mainly from the metallic ions. The half-metallicity of this nanosheet may be improved by both the compress strains and positive charge states. Its magnetic moment per unit cell increases with the positive charge states. If nq = + 2, the magnetic moment per unit cell of this nanosheet is 3.00 μB, which is evidently larger than that of the electric neutral nanosheet Sc2Li2N3. The Curie temperatures of this nanosheet are estimated above the room temperature, suggesting its promising application in spintronics. [ABSTRACT FROM AUTHOR]

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]

Objective: To investigate the reduction in residual ridges of maxillary edentulous models duplicated from old and new complete dentures using the 3-D data analysis., Methods: Twenty-six pairs of maxillary edentulous models copied from the fitting surfaces of new and old upper complete dentures were selected for this study. The 3-D data were collected with a laser scanning system. The data were matched using Geomagic Studio 8 and Rapidform2006 software and then the fitting surfaces of new complete dentures were analyzed in comparison with old ones., Results: The total amount of morphologic change of fitting surface [(39.8+/-14.2)%] was greater than the change of width [(28.2+/-16.0)%]; the area reduction of the residual ridge in anterior region [(43.0+/-15.2)%] was larger than that in posterior region [(36.1+/-14.1)%]; and the area reduction of residual ridge in buccal aspect [(42.9+/-13.8)%] was larger than that in lingual aspect [(35.5+/-15.2)%]. All the differences were statistically significant (P<0.05)., Conclusions: The results of this study reveal that 3-D analysis of the whole change of the residual ridge is significant and verify that the residual ridge resorption of edentulous maxilla in three dimensions is greater in buccal aspect than in lingual aspect and greater in anterior region than in posterior region.