Chen Chaoyu, Avila José, Arezki Hakim, Nguyen Van Luan, Shen Jiahong, Mucha-Kruczyński Marcin, Yao Fei, Boutchich Mohamed, Chen Yue, Lee Young Hee, Asensio Maria C
ANTARES Beamline, Synchrotron SOLEIL & Université Paris-Saclay, L'Orme des Merisiers, Gif sur Yvette CEDEX, France.
Group of Electrical Engineering-Paris, UMR CNRS 8507, CentraleSupélec, Univ. Paris-Sud, Université Paris-Saclay; Sorbonne Universités, UPMC Univ Paris 06, Gif-sur-Yvette CEDEX, France.
Nat Mater. 2018 May;17(5):450-455. doi: 10.1038/s41563-018-0053-1. Epub 2018 Apr 9.
Variations of the lattice parameter can significantly change the properties of a material, and, in particular, its electronic behaviour. In the case of graphene, however, variations of the lattice constant with respect to graphite have been limited to less than 2.5% due to its well-established high in-plane stiffness. Here, through systematic electronic and lattice structure studies, we report regions where the lattice constant of graphene monolayers grown on copper by chemical vapour deposition increases up to ~7.5% of its relaxed value. Density functional theory calculations confirm that this expanded phase is energetically metastable and driven by the enhanced interaction between the substrate and the graphene adlayer. We also prove that this phase possesses distinctive chemical and electronic properties. The inherent phase complexity of graphene grown on copper foils revealed in this study may inspire the investigation of possible metastable phases in other seemingly simple heterostructure systems.
晶格参数的变化会显著改变材料的性能，尤其是其电子行为。然而，对于石墨烯而言，由于其已确立的高面内刚度，相对于石墨的晶格常数变化一直限制在小于2.5%。在此，通过系统的电子和晶格结构研究，我们报告了通过化学气相沉积在铜上生长的单层石墨烯的晶格常数增加至其松弛值的约7.5%的区域。密度泛函理论计算证实，这种扩展相在能量上是亚稳的，并且是由衬底与石墨烯吸附层之间增强的相互作用驱动的。我们还证明了该相具有独特的化学和电子性质。本研究中揭示的在铜箔上生长的石墨烯固有的相复杂性可能会激发对其他看似简单的异质结构系统中可能的亚稳相的研究。
