A simple-and-analytic form for total energy (or ground-state energy) in the uniform three-dimensional electron gas, expressed as a function of any Wigner-Seitz radius rs and relative spin polarization ζ is obtained w...A simple-and-analytic form for total energy (or ground-state energy) in the uniform three-dimensional electron gas, expressed as a function of any Wigner-Seitz radius rs and relative spin polarization ζ is obtained with a very good accuracy of 0.036% from the Stoner model and our interpolation between high-and-low density limits with use of a two-point approach for the correlation energy and spin stiffness at rs = 1 and 70. This suggests a satisfactory desciption of some physical properties such as: paramagnetic-ferromagnetic phase transition and thermodynamic-and-optical phenomena.展开更多
Control over the tunneling current in spintronic devices by electrical methods is an interesting topic, which is experiencing a burst of activity. In this paper, we theoretically investigate the transport property of ...Control over the tunneling current in spintronic devices by electrical methods is an interesting topic, which is experiencing a burst of activity. In this paper, we theoretically investigate the transport property of electrons in a spin-diode structure consisting of a single quantum dot(QD) weakly coupled to one nonmagnetic(NM) and one half-metallic ferromagnet(HFM) leads, in which the QD has an artificial atomic nature. By modulating the gate voltage applied on the dot, we observe a pronounced decrease in the current for one bias direction. We show that this rectification is spin-dependent, which stems from the interplay between the spin accumulation and the Coulomb blockade on the quantum dot. The degree of such spin diode behavior is fully and precisely tunable using the gate and bias voltages. The present device can be realized within current technologies and has potential application in molecular spintronics and quantum information processing.展开更多
Ab initio within the full potential linearized augmented plane wave （FP-LAPW） method with the GGA＋U approach is applied to study the electronic structures of two compounds NaK3（NpO2）4（SO4）4（H2O）2 and NaNpO2SO...Ab initio within the full potential linearized augmented plane wave （FP-LAPW） method with the GGA＋U approach is applied to study the electronic structures of two compounds NaK3（NpO2）4（SO4）4（H2O）2 and NaNpO2SO4H2O. The present calculations show that the major part of the spin magnetic moment in these two compounds is from Np（V） ions, and the origin of the cation-cation interactions between Np comes from the spin polarization effect within Np-ONv-Np bonds.展开更多
Pure single phase of Zn0.95Co0.05O bulks were successfully prepared by solid-state reaction method. The effects of annealing atmosphere and temperature on the room temperature ferromagnetic behavior were investigated....Pure single phase of Zn0.95Co0.05O bulks were successfully prepared by solid-state reaction method. The effects of annealing atmosphere and temperature on the room temperature ferromagnetic behavior were investigated. The results show that the air-annealed samples has similar weak ferromagnetic behavior with the as-sintered samples, but the obvious ferromagnetic behavior is observed for the samples annealed in vacuum or Ar/H2 gas, indicating that the strong ferromagnetism is associated with high oxygen vacancies density. High saturation magnetization Ms=0.73 μB/Co and coercivity Hc=233.8Oe are obtained for the Ar/H2 annealed samples with pure single phase structure when annealing temperature is 600℃.展开更多
The electronic structure and magnetic properties of single layer Ga_(2)O_(3)in the presence of Ga and O vacancies are studied by first principles method based on density functional theory.The results show that the int...The electronic structure and magnetic properties of single layer Ga_(2)O_(3)in the presence of Ga and O vacancies are studied by first principles method based on density functional theory.The results show that the introduction of Ga vacancy(VGa)leads to a non-zero magnetic moment in singlelayer two-dimensional(2D)Ga_(2)O_(3),while VO does not.We find that Ga vacancies in two different symmetric positions can lead to spin polarized ground states.Notably,when the VGa ratio is greater than 1/16(indicating one Ga vacancy per 16 Ga atoms),single-layer 2D Ga_(2)O_(3)exhibits semi-metallic properties and its spin polarization reaches 100%at the Fermi level.Calculations of these two Ga vacancy systems also indicate a potential long-range ferromagnetic order at a high Curie temperature(355.8 K).Finally,a single layer 2D Ga_(2)O_(3)with high GaI vacancy(VGaI)ratio can be used as the ferromagnetic layer to obtain the magnetic tunnel junction(MTJ)with high spin filtering effect at the Fermi level.Ga vacant Ga_(2)O_(3)/MgO/Ga vacant Ga_(2)O_(3)MTJ exhibits excellent spin-filtering effect(with 100%spin polarization)and a giant tunneling magneto resistance(TMR)ratio(up to 1.12×10^(3)%).The results of this paper show that the MTJ based on two-dimensional Ga_(2)O_(3)with room temperature ferromagnetism exhibits reliable performance,showing the possibility of potential applications in spintronics.展开更多
文摘A simple-and-analytic form for total energy (or ground-state energy) in the uniform three-dimensional electron gas, expressed as a function of any Wigner-Seitz radius rs and relative spin polarization ζ is obtained with a very good accuracy of 0.036% from the Stoner model and our interpolation between high-and-low density limits with use of a two-point approach for the correlation energy and spin stiffness at rs = 1 and 70. This suggests a satisfactory desciption of some physical properties such as: paramagnetic-ferromagnetic phase transition and thermodynamic-and-optical phenomena.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11404322,31400810,and 11704180)the Postdoctoral Science Foundation of China(Grant No.2013M541635)the Postdoctoral Science Foundation of Jiangsu Province,China(Grant No.1301018B)
文摘Control over the tunneling current in spintronic devices by electrical methods is an interesting topic, which is experiencing a burst of activity. In this paper, we theoretically investigate the transport property of electrons in a spin-diode structure consisting of a single quantum dot(QD) weakly coupled to one nonmagnetic(NM) and one half-metallic ferromagnet(HFM) leads, in which the QD has an artificial atomic nature. By modulating the gate voltage applied on the dot, we observe a pronounced decrease in the current for one bias direction. We show that this rectification is spin-dependent, which stems from the interplay between the spin accumulation and the Coulomb blockade on the quantum dot. The degree of such spin diode behavior is fully and precisely tunable using the gate and bias voltages. The present device can be realized within current technologies and has potential application in molecular spintronics and quantum information processing.
基金The project supported by National Natural Science Foundation of China under Grant Nos. 10574048 and 20490210
文摘Ab initio within the full potential linearized augmented plane wave （FP-LAPW） method with the GGA＋U approach is applied to study the electronic structures of two compounds NaK3（NpO2）4（SO4）4（H2O）2 and NaNpO2SO4H2O. The present calculations show that the major part of the spin magnetic moment in these two compounds is from Np（V） ions, and the origin of the cation-cation interactions between Np comes from the spin polarization effect within Np-ONv-Np bonds.
基金This work was supported by the National Basic Research Program (973) under Grant No. 2007CB31407 the International S&T Cooperation Program of China under Grant No. 2006DFA53410.
文摘Pure single phase of Zn0.95Co0.05O bulks were successfully prepared by solid-state reaction method. The effects of annealing atmosphere and temperature on the room temperature ferromagnetic behavior were investigated. The results show that the air-annealed samples has similar weak ferromagnetic behavior with the as-sintered samples, but the obvious ferromagnetic behavior is observed for the samples annealed in vacuum or Ar/H2 gas, indicating that the strong ferromagnetism is associated with high oxygen vacancies density. High saturation magnetization Ms=0.73 μB/Co and coercivity Hc=233.8Oe are obtained for the Ar/H2 annealed samples with pure single phase structure when annealing temperature is 600℃.
基金supported by the National Key Research and Development Program of China(2023YFB3609900 and 2021YFA0716400)the General Program of Natural Science Foundation of China(62274134)+4 种基金the National Science Fund for Distinguished Young Scholars(61925404)the Key R&D Project in Xi’an City(2023JH-ZCGJ0013)the Aerospace Institute 771 Innovation Fund(771CX2023007)the Fundamental Research Funds for the Central Universities(YJSJ24020)the Interdisciplinary Cultivation Program of Xidian University(21103240003)。
文摘The electronic structure and magnetic properties of single layer Ga_(2)O_(3)in the presence of Ga and O vacancies are studied by first principles method based on density functional theory.The results show that the introduction of Ga vacancy(VGa)leads to a non-zero magnetic moment in singlelayer two-dimensional(2D)Ga_(2)O_(3),while VO does not.We find that Ga vacancies in two different symmetric positions can lead to spin polarized ground states.Notably,when the VGa ratio is greater than 1/16(indicating one Ga vacancy per 16 Ga atoms),single-layer 2D Ga_(2)O_(3)exhibits semi-metallic properties and its spin polarization reaches 100%at the Fermi level.Calculations of these two Ga vacancy systems also indicate a potential long-range ferromagnetic order at a high Curie temperature(355.8 K).Finally,a single layer 2D Ga_(2)O_(3)with high GaI vacancy(VGaI)ratio can be used as the ferromagnetic layer to obtain the magnetic tunnel junction(MTJ)with high spin filtering effect at the Fermi level.Ga vacant Ga_(2)O_(3)/MgO/Ga vacant Ga_(2)O_(3)MTJ exhibits excellent spin-filtering effect(with 100%spin polarization)and a giant tunneling magneto resistance(TMR)ratio(up to 1.12×10^(3)%).The results of this paper show that the MTJ based on two-dimensional Ga_(2)O_(3)with room temperature ferromagnetism exhibits reliable performance,showing the possibility of potential applications in spintronics.
