Two-dimensional(2D)nanomaterials with bipolar magnetism show great promise in spintronic applications.Manipulating carriers'spin-polarized orientation in bipolar magnetic semiconductor(BMS)requires a gate voltage,...Two-dimensional(2D)nanomaterials with bipolar magnetism show great promise in spintronic applications.Manipulating carriers'spin-polarized orientation in bipolar magnetic semiconductor(BMS)requires a gate voltage,but that is volatile.Recently,a new method has been proposed to solve the problem of volatility by introducing a ferroelectric gate with proper band alignment.In this paper,we predict that the PdX_(2)(X=F,Cl,Br,I)monolayers are 2D ferromagnetic BMS with dynamic stability,thermal stability,and mechanical stability by first-principles calculations.The critical temperatures are higher than the boiling point of liquid nitrogen and the BMS characteristics are robust against external strains and electric fields for PdCl_(2) and PdBr_(2).Then,we manipulate the spin-polarization of PdCl_(2) and PdBr_(2) by introducing a ferroelectric gate to enable magnetic half-metal/semiconductor switching and spin-up/down polarization switching control.Two kinds of spin devices(multiferroic memory and spin filter)have been proposed to realize the spin-polarized directions of electrons.These results demonstrate that PdCl_(2) and PdBr_(2) with BMS characters can be widely used as a general material structure for spintronic devices.展开更多
LiMn 2O 4-x F x prepared by the sol gel method has a perfect crystal formation .The crystal particle size of the material was medium and distributed uniformly. The substitution of F for O increased the specific...LiMn 2O 4-x F x prepared by the sol gel method has a perfect crystal formation .The crystal particle size of the material was medium and distributed uniformly. The substitution of F for O increased the specific capacity of the material at the cost of the cycleability .The explanation of this results is that the F decreases the valence of Mn,that is,more Mn 3+ and less Mn 4+ exist in the material.The increase of Mn 3+ will improve the initial specific capacity and Mn 3+ is the original reason for Jahn Teller effect that caused the poor cycleability of the cathode material by the micro distortion of the crystal structure. In addition, the expanded measurement of the crystal lattice is also the reason for the poor cycleability.Therefore,the results of F substitution and cation substitution are opposite.If the two methods are combined,they can compensate the inability each other and the satisfactory results may be obtained.展开更多
基金Project supported by the Taishan Scholar Program of Shandong Province,China (Grant No.ts20190939)the Independent Cultivation Program of Innovation Team of Jinan City (Grant No.2021GXRC043)+1 种基金the National Natural Science Foundation of China (Grant No.52173283)the Natural Science Foundation of Shandong Province (Grant No.ZR2020QA052)。
文摘Two-dimensional(2D)nanomaterials with bipolar magnetism show great promise in spintronic applications.Manipulating carriers'spin-polarized orientation in bipolar magnetic semiconductor(BMS)requires a gate voltage,but that is volatile.Recently,a new method has been proposed to solve the problem of volatility by introducing a ferroelectric gate with proper band alignment.In this paper,we predict that the PdX_(2)(X=F,Cl,Br,I)monolayers are 2D ferromagnetic BMS with dynamic stability,thermal stability,and mechanical stability by first-principles calculations.The critical temperatures are higher than the boiling point of liquid nitrogen and the BMS characteristics are robust against external strains and electric fields for PdCl_(2) and PdBr_(2).Then,we manipulate the spin-polarization of PdCl_(2) and PdBr_(2) by introducing a ferroelectric gate to enable magnetic half-metal/semiconductor switching and spin-up/down polarization switching control.Two kinds of spin devices(multiferroic memory and spin filter)have been proposed to realize the spin-polarized directions of electrons.These results demonstrate that PdCl_(2) and PdBr_(2) with BMS characters can be widely used as a general material structure for spintronic devices.
文摘LiMn 2O 4-x F x prepared by the sol gel method has a perfect crystal formation .The crystal particle size of the material was medium and distributed uniformly. The substitution of F for O increased the specific capacity of the material at the cost of the cycleability .The explanation of this results is that the F decreases the valence of Mn,that is,more Mn 3+ and less Mn 4+ exist in the material.The increase of Mn 3+ will improve the initial specific capacity and Mn 3+ is the original reason for Jahn Teller effect that caused the poor cycleability of the cathode material by the micro distortion of the crystal structure. In addition, the expanded measurement of the crystal lattice is also the reason for the poor cycleability.Therefore,the results of F substitution and cation substitution are opposite.If the two methods are combined,they can compensate the inability each other and the satisfactory results may be obtained.
