A two-dimensional ErCu2 intermetallic compound on Cu(111) with moire´-pattern-modulated electronic structures
A two-dimensional ErCu2 intermetallic compound on Cu(111) with moire´-pattern-modulated electronic structures
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Cu(111) 上的二维 ErCu2 金属间化合物，具有莫尔图案调制电子结构
DOI：
10.1039/c9cp05585a
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Xudong Xiao
中科院分区：
文献类型：
--
作者：
Chaoqiang Xu;Kejie Bao;Y;e Que;Yuan Zhuang;Xiji Shao;Kedong Wang;Junyi Zhu;Xudong Xiao
A rare-earth compound on a metal may form a two-dimensional (2D) intermetallic compound whose.properties can be further modulated by the underlying substrate periodicity and coupling. Here, we.present a combinational and systematic investigation using scanning tunneling microscopy/spectroscopy.(STM/STS) and density functional theory (DFT) calculations on erbium (Er) on Cu(111). Experimentally, an.intriguing growth mode transition from a branched island to a fractal-like island has been observed.depending on whether the deposition process of Er is interrupted for a certain duration: post-deposition.effects, such as nucleation and island growth controlled by diffusion, play an essential role in altering the.Er island edge and its activity. Upon annealing, the branched Er islands become strands of amorphous.surface alloy; in contrast, the fractal-like islands (with additional Er atoms on top) give rise to a.monolayer thick 2D ErCu2 intermetallic compound and display a moire´ pattern. Theoretically, using DFT.calculations, we found that the characteristic energy states, particularly the state in the unoccupied region.around 582–663 meV, of the 2D ErCu2 intermetallic compound are position-dependent, consistent with.STS measurements. The moire´ pattern originating from the mismatch of the periodicities of the ErCu2 layer.and the Cu(111) surface was identified to be responsible for the observed periodic modulation on the.coupling interaction that affects the electronic structures. Our further DFT calculations on a freestanding.ErCu2 monolayer found it to be a 2D ferromagnet with topological band structures. Our work.should stimulate further studies on such 2D rare-earth-based nanostructures and exploration of the use.of the tunable electronic structures in such atomically-thin layers
