title: The favourable large misorientation angle grain boundaries in graphene.
abstract: A grain boundary (GB) in graphene is a linear defect between two specifically oriented graphene edges, whose title angles are denoted as θ1 and θ2, respectively. Here we present a systematic theoretical study on the structure and stability of GBs in graphene as a function of the misorientation angle, Φ = (θ1-θ2) and the GB orientation in multi-crystalline graphene, which is denoted by Θ = (θ1 + θ2). It is surprising that although the number of disorders of the GB, i.e., the pentagon-heptagon pairs (5|7s), reaches the maximum at Φ∼ 30°, the GB formation energy versus the Φ curve reaches a local minimum. The subsequent M-shape of the Efvs. the Φ curve is due to the strong cancellation of the local strains around 5|7 pairs by the "head-to-tail" formation. This study successfully explains many previously observed experimental puzzles, such as the multimodal distribution of GBs and the abundance of GB misorientation angles of ∼30°. Besides, this study also showed that the formation energy of GBs is less sensitive to Θ, although the twin boundaries are slightly more stable than others.
authors.affiliation: Institute of Textile and clothing, Hong Kong Polytechnic University, Hong Kong, China. feng.ding@polyu.edu.hk john.xin@polyu.edu.hk.
authors.forename: Xiuyun
authors.initials: X
authors.lastname: Zhang
authors.forename: Ziwei
authors.initials: Z
authors.lastname: Xu
authors.forename: Qinghong
authors.initials: Q
authors.lastname: Yuan
authors.forename: John
authors.initials: J
authors.lastname: Xin
authors.forename: Feng
authors.initials: F
authors.lastname: Ding