Controllable inversion symmetry breaking in single layer graphene induced by sub-lattice contrasted charge polarization. (15th August 2020)

• Record Type: Journal Article
• Authors: Shi, Beibei; Xiao, Yingdong; Han, Tianyang; Cheng, Haotian; Zhang, Jincan; Jiang, Qiao; Peng, Hailin; Zhang, Han; Zhu, Xing; Fang, Zheyu
• Is Part Of: Carbon. Volume 163(2020)
• Page Start: 63
• Page End: 69
• Publication Date: 2020-08-15
• Subjects: Carbon -- Periodicals; Carbone -- Périodiques; Koolstof; Toepassingen; Electronic journals; 546.681
• DOI: 10.1016/j.carbon.2020.03.018
• Languages: English
• ISSNs: 0008-6223

Abstract

Abstract: It has been revealed that inversion symmetry breaking in graphene could induce non-trivial Berry curvature, which leads to topologically protected valleytronic applications. Here, we propose an active controllable way of realizing the inversion symmetry breaking of single layer graphene, which is induced by the contrasted AB sub-lattice charge polarization. Our theory model indicates the split of in-plane optical phonons (iTO/iLO) at Γ point is the direct result of inversion symmetry breaking in single layer graphene. Density functional theory calculation was used to quantify the sub-lattice charge polarization and the split of iTO/iLO phonons under the external in-plane electric field, which was further confirmed by Raman spectroscopy. We believe that the method of symmetry manipulation by external in-plane electric field advances fundamental comprehension for the inner mechanism of topological phase transition of graphene. Graphical abstract: We propose a controllable method to induce topological phase transition of graphene into topological non-trivial material in the way of symmetry manipulation by inducing sub-lattice contrasted charge polarization in the shape of in-plane external electric field. With Raman spectroscopy, the difference between ITO and ILO phonon can be measured. We demonstrate the split of G-peak is proportional to in-plane electric field strength applied on graphene, which is confirmed by theoretical calculation and experiments. Image 1