Peculiarities of interaction of the p_z-, π- electrons and the σ_p-holes at the top 1-6 layers of HOPG

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• 作者：A.P. Dementjev ; ^{demcarbon@yandex.ru} ; K.E. Ivanov
• 关键词：Auger spectroscopy ; Graphene ; HOPG
• 刊名：Applied Surface Science
• 出版年：2017
• 出版时间：31 March 2017
• 年：2017
• 卷：399
• 期：Complete
• 页码：551-554
• 全文大小：497 K
• 卷排序：399

文摘

The present work continues the analysis of results of Dementjev et al. (2015) in order to identify the interlayer interactions of the π-bands. Analysis of the N(E) C KVV Auger spectra of highly-ordered pyro-graphite showed the absence of the electron exchange between the π-bands in 1–6 layers. Since the π-bands are formed by the pz → π transitions, one can suggest that the π-band occupation at each graphene layer is formed by the pz-electrons of this layer. Since the pz electrons belong to the σp-bands, the pz → π transitions in the σp-bands in each of 2–6 graphene layers result in formation of holes H, whose concentration is equal to the concentration of electrons in the π-bands [Hi] [πi]. This shows the origin of the ambipolar conductivity in graphene.The absence of the electronic interaction between the π-bands allows a suggestion that the interaction between top six graphene layers is due to the van der Waals electrostatic attractive forces. These forces promote the pz → π transitions in each of the 2–6 graphene layers and depend on the number of graphene layers above. The N(E) C KVV Auger spectra allow identification of number (1–6) of graphene layers and the π-band occupation at each of the layer. For the first time a specification of the van der Waals forces in HOPG was done.