Origami-controlled strain engineering of tunable flat bands and correlated states in folded graphene

• Published in: arXiv.org
• Main Authors: Li-Zhen, Yang, Ling-Hui, Tong, Cheng-Sheng, Liao, Wu, Qilong, Fu, Xiaoshuai, Yue-Ying, Zhou, Tian, Yuan, Zhang, Li, Zhang, Lijie, Meng-Qiu Cai, He, Lin, Qin, Zhihui, Long-Jing, Yin
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 22.04.2022
• Subjects: Banded structure; Correlation; Folding; Graphene; Magnetic fields; Physics - Mesoscale and Nanoscale Physics
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2204.10469

Flat electronic bands with tunable structures offer opportunities for the exploitation and manipulation of exotic interacting quantum states. Here, we present a controllable route to construct easily tunable flat bands in folded graphene, by nano origami-controlled strain engineering, and discover correlated states in this system. Via tearing and folding graphene monolayer at arbitrary step edges with scanning tunneling microscope manipulation, we create strain-induced pseudo-magnetic fields as well as resulting flat electronic bands in the curved edges of folded graphene. We show that the intensity of the pseudo-magnetic field can be readily tuned by changing the width of the folding edge due to the edge-width-dependent lattice deformation, leading to the well adjustability of the geometry of flat bands in folded graphene. Furthermore, by creating expected dispersionless flat bands using this technique, the correlation-induced splits of flat bands are successfully observed in the density of states when these bands are partially filled. Our experiment provides a feasible and effective pathway to engineer the system with tunable flat band structures, and establishes a new platform that can be used to realize devisable strain and interaction induced quantum phases.