First-principles study of Mn adsorption on Al4C3(0001) surface
First-principles study of Mn adsorption on Al4C3(0001) surface
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DOI：
10.1016/j.apsusc.2015.11.262
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发表时间：
2016-02
影响因子：
6.7
通讯作者：
L. Yao;Ke Li;N. Zhou
中科院分区：
文献类型：
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作者：
L. Yao;Ke Li;N. Zhou
采用基于密度泛函理论的第一性原理计算方法，研究了Mn原子在0.25 ML和0.5 ML下，在Al和C封端的Al 4C 3（0001）表面的吸附能、稳定性、电子结构和成键.结果表明，Mn在C端Al 4C 3（0 0 0 1）表面上的吸附结构比在Al端表面上的吸附结构更稳定.对于Mn在Al封端表面上的吸附，Mn更有利于驻留在H1位上。对于Mn在C端表面的吸附，H′ 1位的吸附结构是最稳定的.通过电子结构和成键分析，发现Mn原子与Al端表面形成金属/共价混合键，而Mn原子与C端表面形成共价键。根据层间距计算，Mn吸附后Al 4C 3（0 0 0 1）表面发生了重构，从而影响Mg原子在Al 4C 3（0 0 0 1）表面的堆积.上述分析为高Mn含量不利于α-Mg晶粒中Al 4C 3颗粒的异质形核的实验现象提供了有效的理论支持。
First-principle calculation based on the density functional theory was adopted to investigate the adsorption energy, stability, electronic structure and bonding of Mn atom adsorption on Al-terminated and C-terminated Al4C3(0 0 0 1) surface under 0.25 ML and 0.5 ML. Results show that the structure of Mn adsorption on C-terminated Al4C3(0 0 0 1) surface is more stable than that on Al-terminated surface according to the formation energy calculation. For Mn adsorption on Al-terminated surface, Mn is more favorable to reside at the site H1comparing with other sites. As well, for Mn adsorption on C-terminated surface, the structure of Mn adsorption at site H′1is the most stable one. By analyzing the electronic structure and bonding, it is found that the mixed metallic/covalent bonds are formed between Mn atoms and Al-terminated surface, while the covalent bonds are formed between Mn atoms and C-terminated surface. According to the interlayer spacing calculation, Al4C3(0 0 0 1) surfaces are reconstructed after Mn adsorption, which in turn affect the following stacking of Mg atoms on Al4C3(0 0 0 1) surface. The above analysis provided effective theoretical support to the experimental phenomenon that high Mn content has negative influence on the heterogeneous nucleation of Al4C3particles for α-Mg grains.