T-ZrS2 nanoribbons: structure and electronic properties

Recently, monolayer and few layers of trigonal phases of zirconium disulfide ( T-ZrS2) sheets were obtained experimentally on hexagonal boron nitride using an evaporation technique. On the basis of these previous results, we report the structural and electronic properties of armchair nanoribbons ( ANRs) and zigzag nanoribbons ( ZNRs) of T-ZrS2 by means of density functional theory. According to our results, both ANRs and ZNRs are nonmagnetic semiconductors similar to a two-dimensional T-ZrS2 monolayer. The semiconducting character is not altered by termination of the edge atoms with hydrogen. The band gaps are associated with the ribbon widths and edge structures. The band gaps of bare and H-terminated ANR-ZrS2 decrease exponentially, whereas the band gaps of ultra-narrow zigzag nanoribbons oscillate slightly with increasing ribbon width. Although the band gaps of bare ANRs approach that of 2D T-ZrS2, other structures have larger band gaps than the monolayer with increasing ribbon width. The cohesive and formation energies of bare ANRs and ZNRs converge rapidly to that of the 2D T-ZrS2 structure with increasing ribbon width.