Bulk and Surface Simulation Studies of La1-xCaxMnO3
Bulk and Surface Simulation Studies of La1-xCaxMnO3
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La1-xCaxMnO3 的本体和表面模拟研究
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
S. Woodley
中科院分区：
文献类型：
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作者：
M. Akhtar;C. Catlow;B. Slater;A. Walker;S. Woodley
采用体相和表面模拟技术研究了La_（1-x）Ca_xMnO_3的结构性质。势参数再现的晶体结构的两个终端组合物，给出了良好的协议与实验数据。计算得到的晶格参数随Ca浓度的变化规律与实验值吻合较好。我们的计算预测形成的固溶体，在非常低的温度和附近的x = 1/2，阳离子优先顺序上的A和B网站。阳离子有序的驱动机制来自库仑和离子尺寸项，相对比例取决于组成。然而，在通常发生高温合成的温度下，阳离子的排序是随机的。表面能计算为（010）和（110）表面的最终组合物：在LaMnO 3，Mn-终止层更稳定，而Ca-终止层被发现是更稳定的CaMnO 3系统。有人建议，T…
The structural properties of La1-xCaxMnO3 are investigated by employing bulk and surface simulation techniques. The potential parameters reproduce the crystal structures of both end compositions, giving good agreement with experimental data. The calculated variation of the lattice parameters with Ca concentration also agrees with experimental values. Our calculations predict the formation of a solid solution and that, at very low temperatures and near x = 1/2, the cations preferentially order on both A and B sites. The driving mechanism for cation ordering arises from both the coulomb and ion-size terms, with the relative proportions depending on composition. However, at temperatures where high-temperature synthesis normally occurs, the ordering of the cations is random. Surface energies are calculated for (010) and (110) surfaces for the end compositions: in LaMnO3, Mn-terminated layers are more stable, whereas Ca-terminated layers are found to be more stable for the CaMnO3 system. It is proposed that t...