Strain engineering of electronic and magnetic properties of Ga₂S₂ nanoribbons

Using first-principles calculations, we study the tailoring of the electronic and magnetic properties of gallium sulfide nanoribbons (Ga₂S₂NRs) by mechanical strain. Hydrogen-passivated armchair- and zigzag-edged NRs (ANRs and ZNRs) with different widths are investigated. Significant effects in band gap and magnetic properties are found and analyzed. First, the band gaps and their nature of ANRs can be largely tailored by a strain. The band gaps can be markedly reduced, and show an indirect-direct (I-D) transition under a tensile strain. While under an increasing compressive strain, they undergo a series transitions of I-D-I-D. Five strain zones with distinct band structures and their boundaries are identified. In addition, the carrier effective masses of ANRs are also tunable by the strain, showing jumps at the boundaries. Second, the magnetic moments of (ferromagnetic) ZNRs show jumps under an increasing compressive strain due to spin density redistribution, but are unresponsive to tensile strains. The rich tunable properties by stain suggest potential applications of Ga₂S₂NRs in nanoelectronics and optoelectronics. (paper)