Carbon nanotubes rolled from Me-graphene

The nanotubes rolled from the monolayer Me-graphene (Me-CNTs) are proposed in this work with the aid of the density functional theory (DFT) simulations. Due to the square lattice of the monolayer Me-graphene, any chirality for an (n,m) Me-CNT system is feasible. The thinnest (n,0) and (n,n) Me-CNTs are confirmed by their lattice dynamic and thermodynamic stabilities. Moreover, the mechanical features of the Me-CNT systems are also estimated. Their electronic properties are carefully investigated. An even-odd relation of the band gaps in the (n,0) case is found. The fundamental cause of this relation is clearly discussed with the aid of the band folding theory. Advantageously, the band gap of an Me-CNT should vary within the range of 1.79 eV to 2.92 eV, indicating the application potentials in the field of the solar energy conversion. Furthermore, the band edge arrangements of the (n,0) Me-CNTs endow these one-dimensional (1D) materials with the application potential in photocatalytic water splitting.