Twinning is a known accommodation mechanism of graphene that results in low-energy microstructures or twins. In view of their mechanical stability, twins suggest themselves as a possible means of introducing extended defects in graphene leading to the opening of transmission band gaps. We investigate charge-carrier transmission across the twin structures in graphene using the Landauer-Büttiker (LB) formalism in combination with a tight-binding model. We verify the approach by means of selected comparisons with Density Functional Theory (DFT) and non-equilibrium Green's function (NEGF) calculations using the code SIESTA and TRANSIESTA. The calculations reveal that graphene twins open transport gaps depending on the twin geometry up to maximum of 1.15 eV. As previously reported for grain boundaries, we find that localized states arise at dislocation cores in the twin boundaries that introduce peaks near the Fermi level.

中文翻译：

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石墨烯中双胞胎之间的电荷载流子传输


孪晶是一种已知的石墨烯调节机制，可产生低能微结构或孪晶。考虑到它们的机械稳定性，孪晶表明它们是在石墨烯中引入扩展缺陷从而导致传输带隙打开的一种可能方法。我们使用 Landauer-Büttiker (LB) 形式与紧束缚模型相结合，研究石墨烯中孪生结构中的电荷载流子传输。我们通过使用代码 SIESTA 和 TRANSIESTA 与密度泛函理论 (DFT) 和非平衡格林函数 (NEGF) 计算进行选择性比较来验证该方法。计算表明，石墨烯孪晶打开的传输间隙取决于孪晶几何形状，最大可达 1.15 eV。正如之前报道的晶界，我们发现局域态出现在孪晶界的位错核心处，在费米能级附近引入峰值。