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Effect of C doping on the structural and electronic properties of LiFePO<sub>4</sub>:A first-principles investigation 下载免费PDF全文
Using first-principles calculations within the generalized gradient approximation (GGA) +U framework, we investigate the effect of C doping on the structural and electronic properties of LiFePO 4 . The calculated formation energies indicate that C doped at O sites is energetically favoured, and that C dopants prefer to occupy O 3 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 Fe 3+ , and it will be helpful to the hopping of electrons. 相似文献
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采用基于密度泛函理论(DFT)广义梯度近似(GGA)下的第一性原理方法系统地研究了不同覆盖度下O在Ni(111)表面的吸附特性.计算结果表明,O在Ni(111)表面的稳定吸附位为三重面心立方(fcc)洞位,吸附能随着覆盖度的增加而减小,O诱导Ni(111)表面功函数的变化量与覆盖度成近线性关系,并随着覆盖度的增加而增大.同时,通过对电子密度和分波态密度的分析发现:O在Ni(111)表面的吸附使得Ni表面电子向O原子转移,形成表面偶极矩,导致功函数增加;表面Ni原子的3d轨道和O的2p轨道通过耦合、杂化作用形成成键态和反键态,而反键态几乎不被占据,因而O—Ni键相互作用比较强,吸附能较大.
关键词:
表面吸附
密度泛函理论
吸附能
功函数 相似文献
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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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