Structural Features and Electronic Properties of MgO Nanosheets and Nanobelts

On the basis of first principles calculations, we systematically investigate the structural features, stabilities, and electronic properties of the MgO nanosheets and corresponding nanobelts with different widths. For the MgO(100) sheet, two new kinds of structures characterizing rumpling and wavelike features are found to be more stable than the flat one. Our calculations predict that these two kinds of MgO(100) and MgO(111) nanosheets exhibit semiconductive properties, with the band gaps varying from 4.23 to 4.38 eV. Moreover, their band gaps vary as different functions of the applied strain. In addition, we find that the MgO(111) nanobelts with zigzag edges show metallic behavior whereas the MgO(111) nanobelts with armchair edges and MgO(100) nanobelts exhibit semiconductive properties. In particular, the band gaps for the semiconductive nanobelts can be manipulated from 2.75 to 3.95 eV by the width of the nanobelts. These aspects provide these nanobelts with promising applications in spintronics and nanoscaled ultraviolet photoelectronic devices.