Abstract
Two-dimensional (2D) semiconductor gallium monochalcogenides GaX (X = S, Se) hold great promise for future electronics and optics. In this paper, geometrical structures and electronic properties of quasi-1D pristine gallium monochalcogenide GaX (X = S, Se) nanoribbons (NRs) have been studied by means of first-principles calculations, aiming to address the edge effects of 2D GaX (X = S, Se) nanoflakes. The armchair NRs are nonmagnetic semiconductors, in which the edge distortion is observed. In the zigzag GaX NRs, they present metallic behavior for both spin-up and spin-down channels with great magnetism, except for 1-Z-NR GaSe and GaS. The spin polarization in the zigzag GaX (X = S, Se) NRs mainly originates from the unpaired electrons on the edge Ga atoms. Our present work may well complement the current studies on the layered gallium monochalcogenides GaX (X = S, Se), and other quasi-1D NRs (e.g. graphene, ZnO, and MoS2).