Grain boundary and its hydrogenated effect in stanene

The geometric and electronic properties of grain boundary (GB) in two-dimensional (2D) stanene have been investigated by first-principles calculations. Four typical GB structures with particularly low formation energies were found. These extended defects act as quasi-one-dimensional semiconductor or metallic wires depending on their geometric structures. Moreover, they are reactive and the adsorption of H atoms at the GB region is more stable than the stanene bulk region. A single H adsorption poses a drastic effect on the electronic behavior of GB defects, and the band structures can be tuned by the coverages of H adsorption at these GB defects in stanene. The present results indicate that GBs are important defects in stanene which may be useful for nanomaterial devices