Probing interlayer interactions between graphene and metal substrates by supersonic rare-gas atom scattering
Probing interlayer interactions between graphene and metal substrates by supersonic rare-gas atom scattering
复制标题
DOI：
10.1103/physrevb.91.155403
复制
发表时间：
2015-04
影响因子：
3.7
通讯作者：
H. Shichibe;Y. Satake;K. Watanabe;A. Kinjyo;A. Kunihara;Y. Yamada;M. Sasaki;W. Hayes;J. Manson
中科院分区：
文献类型：
--
作者：
H. Shichibe;Y. Satake;K. Watanabe;A. Kinjyo;A. Kunihara;Y. Yamada;M. Sasaki;W. Hayes;J. Manson
我们证明了高表面敏感的超音速稀有气体(He、Ar和Xe)原子散射，在量子和经典两种情况下，都可以探测和量化石墨烯单分子膜与金属衬底之间的层间相互作用，根据与表面简正振动相对应的德拜温度和表面有效质量。作为强相互作用石墨烯和弱相互作用石墨烯的模型，我们分别研究了石墨烯在Ru(0001)和Pt(111)上的相互作用。将Ar和Xe的实验数据与基于经典光滑表面模型的理论模拟结果进行了比较。对于Gr/Pt(111)，我们发现稀有气体束的散射模式，包括氦束的德拜-沃勒衰减，与高取向热解石墨(HOPG)的散射模式非常相似，这表明石墨烯-铂(111)相互作用非常类似于范德华相互作用。相反，对于Gr/Ru(0001)体系，我们发现较小的德拜-沃勒衰减和较大的表面有效质量，表明石墨烯在Ru(0001)上与衬底紧密结合。此外，Gr/Ru(0001)的Ar和Xe散射谱中的不对称光谱形状被解释为对应于莫尔图案的层间相互作用的横向分布的结果。结果表明，莫尔条纹的“谷区”具有较高的有效质量，反映了与衬底的较强成键，这是该系统所报道的He光束高反射率的原因之一。另一方面，发现“山丘”区的有效质量与HOPG的有效质量相似，这表明该区与衬底有很好的去耦合。这些结果表明，原子散射具有独特的探测和评估分子-底物相互作用及其空间分布的能力。
We demonstrate that highly surface-sensitive supersonic rare-gas (He, Ar, and Xe) atom scattering, in both the quantum and classical regimes, can probe and quantify the interlayer interactions between graphene monolayers and metal substrates in terms of the Debye temperature corresponding to the surface normal vibration, and the surface effective mass. As models of the strongly and weakly interacting graphene, we investigated two systems, graphene on Ru(0001) and Pt(111), respectively. The experimental data for Ar and Xe are compared with the results from theoretical simulations based on the classical smooth surface model. For gr/Pt(111) we find that the scattering pattern of the rare-gas beam, including the Debye-Waller attenuation of the He beam, are quite similar to that from highly oriented pyrolytic graphite (HOPG); this suggests that the graphene-Pt(111) interaction is much like a van der Waals interaction. On the contrary, for the gr/Ru(0001) system, we find a smaller Debye-Waller attenuation and a larger surface effective mass, indicating that graphene on Ru(0001) is tightly bonded to the substrate. Furthermore, asymmetrical spectral shapes in the Ar and Xe scattering spectra from gr/Ru(0001) are interpreted as a result of the lateral distribution of the interlayer interaction corresponding to the moiré pattern. It is found that the “valley” region of the moiré pattern has high effective mass reflecting stronger bonding to the substrate, contributing to the high reflectivity of the He beam reported for this system. On the other hand, the effective mass of the “hill” region is found to be similar to that of HOPG, indicating that this region is well decoupled from the substrate. These results demonstrate a unique capability of atom scattering to probe and evaluate the molecule-substrate interaction and its spatial distributions.