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利用第一性原理计算得到C掺杂ZnO的电子结构,发现系统具有半金属的电子结构.从态密度的分析可以看到Zn-3d和C-2p电子具有强烈的杂化作用,这是体系具有相对稳定铁磁基态的原因.利用第一性原理得到的磁性耦合强度并结合蒙特卡罗模拟得到了C掺杂浓度为555%,833%,125%的ZnO1-xCx分别具有210 K,260 K,690 K的居里温度.同时,详细地分析了C掺杂引起的电子转移和C,Zn,O的s,p和d电子的自旋向上和自旋向下电子数的变化.通过比较研究,发现ZnO1-xCx的局域磁矩主要来源于Zn-3d 电子和C-2p 电子之间的相互作用,而局域磁矩耦合倾向于RKKY耦合.
关键词:
1-xCx')" href="#">ZnO1-xCx
磁性
第一性原理
蒙特卡罗模拟 相似文献
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Effect of C doping on the structural and electronic properties of LiFePO4: A first-principles investigation 下载免费PDF全文
Using first-principles calculations within the generalized gradient approximation (GGA) +U framework, we inves- tigate the effect of C doping on the structural and electronic properties of LiFePO4. The calculated formation energies indicate that C doped at O sites is energetically favoured, and that C dopants prefer to occupy 03 sites. The band gap of the C doped material is much narrow than that of the undoped one, indicating better electro- conductive properties. To maintain charge balance, the valence of the Fe nearest to C appears as Fe3+, and it will be helpful to the hopping of electrons. 相似文献
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为了使用低成本、无创伤且易操作的方法评估人体心血管的健康状况,设计一个基于ARM11(S3C6410)的无创心血管健康评估系统,该系统由无创心血管参数检测探头、嵌入式人机交互平台和内嵌的健康评估模型三个部分组成。基于能量代谢守恒法、指端容积脉搏波检测等研制出无创检测探头,用于测量血压、血流速度和血糖等人体参数,采用蓝牙4.0设备将数据传输至嵌入式人机交互平台,数据经改进后的国人缺血性心血管病(ICVD)10年发病危险评估模型得出健康评估结果。实验结果表明该方法所得评估结果和微创真值经原始ICVD评估模型所得评估结果的Pearson相关系数为0.91(Spearman相关系数为0.891),说明该方法是可行的。 相似文献
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Based on the Monte Carlo method, we simulate the magnetization curves with various magnetic field orientations for various single Co nanowires at room temperature. The simulated switching field as a function of angle between the field and the wire axis is consistent well with the experimental data. Correspondingly, the coercivity as a function of angle θ is presented, which together with the switching field plays an important role on explaining the magnetic reversal mechanism. It is found that the angular dependence of coercivity depends on the diameter of nanowires, and the coercivity and switching field versus θ deviate markedly from the prediction from the classical uniform rotation mode in the chain-of-sphere model. Furthermore, the magnetic reversal configurations display that magnetization reversal in the wires with small diameters is a nucleation-propagation process, and it is similar to the curling spread process in the larger wires. 相似文献
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