论文标题

建模具有弹性多站点相互作用的Cu(001)上氮C(2x2)岛的大小

Modelling the size of Nitrogen c(2x2) islands on Cu(001) with elastic multisite interactions

论文作者

Kappus, Wolfgang

论文摘要

用于Adatom相互作用的扩展弹性特征向量方法应用于Cu(001)上的氮C(2x2)原子岛模型。考虑了Adatom单体或二聚体之间的振荡相互作用。 Adatoms的有吸引力的对相互作用能够描述聚集,但无法解释岛屿的大小。但是,如果正确调整了相互作用参数,则由二聚体产生的多站点相互作用可以解释岛屿的大小。当令人难以置信的单体二聚体相互作用平衡排斥性单体相互作用时,就会形成有限的岛屿。最近的邻居吸引力和S-3排斥的简单模型被用作交互参数搜索的示例。先前的实验研究表明,在低覆盖区域中,氮原子聚集到约5 nm x 5 nm大小的分离的方岛,具有C(2x2)结构。随着覆盖范围的增加,这些岛屿形成了常规图案,但不会触及约0.4个单层。先前的实验和计算表明,方岛模式显示出明显的弹性效应。已经分析了氮岛中不同的Adatom结构,二聚体步骤模型能够重现实验发现的岛屿大小。该模型需要由氮气构成的二聚体之间的分子键。该模型还用于计算岛屿之间的弹性相互作用,并根据实验发现的岛屿模式对其进行检查。讨论了模型的缺点和局限性,并提出了开放问题。

An extended elastic eigenvector approach for adatom interactions is applied to model Nitrogen c(2x2) Atom islands on Cu(001). Oscillating interactions between adatom monomers or dimers are considered. Attractive pair interactions of adatoms are able to describe agglomeration but fail to explain the size of islands. Multisite interactions created by dimers, however, can explain the size of islands if an interaction parameter is adjusted properly. Finite size islands are formed when repulsive monomer interactions are balanced by attractive monomer-dimer interactions. A simple model of nearest neighbour attraction and s-3 repulsion is used as an example for the interaction parameter search. Previous experimental studies have shown that in the low coverage region Nitrogen atoms agglomerate to isolated square islands of about 5 nm x 5 nm size with a c(2x2) structure. With increasing coverage those islands form regular patterns but do not touch below about 0.4 monolayers. Previous experiments and calculations have shown that the square island pattern show significant elastic effects. Different adatom structures within the Nitrogen islands have been analyzed, a dimer step model is able to reproduce the experimentally found island size. This model requires a molecular bond between dimers formed by Nitrogen adatoms. The model is also used to compute elastic interactions between islands and to check it against the experimentally found island pattern. Shortcomings and limitations of the model are discussed and open questions are formulated.

扫码加入交流群

加入微信交流群

微信交流群二维码

扫码加入学术交流群,获取更多资源