▎ 摘　　要

The variable frequency characteristics of functionalized single-layered graphene sheets (SLGSs) are studied using molecular dynamics simulations. Two typical functional groups, the hydroxyl and carboxyl groups (-OH and -COOH groups), are considered in the vibration simulations of SLGSs. The functional groups may bend the SLGS surface into many ripples and disturb the mass distributions, which have a great effect on the variation characteristics of the SLGSs. Compared with the pristine SLGS, the SLGSs with randomly distributed functional groups have degenerated vibration characteristics, while the SLGSs regularly functionalized with groups have amazingly increased resonant frequencies. Thus we may design a functional group-guided variable frequency graphene resonator by tuning the distribution manner of the groups. Our results reveal that the resonant frequency shift of such a graphene resonator may reach 67%-135% of the resonance frequency of a bare graphene resonator. These results will give a significant guide to designing SLGS nanomechanical resonators having variable frequencies in the terahertz range.