Tunable mechanical, electronic and magnetic properties of monolayer C3N nanoribbons by external fields

Two-dimensional (2D) polyaniline with C3N stoichiometry, is a newly fabricated layered material that has been expected to possess fascinating electronic, thermal, mechanical and chemical properties. The nature of its counterpart nanoribbons offering even more tunability in properties because of the unique quantum confinement and edge effect, however, has not been revealed yet. Here we systemically study the mechanical, electronic and magnetic properties for various nanoribbons cutting from a monolayer C3N sheet along the typical crystallographic orientations. By the first-principles calculations we find that C3N nanoribbons exhibit sensitive responses to the externally applied electric field and strain. Specifically, the spin-selective half-metallicity depends on the external electric field or strain, as well as the ribbon width. For the asymmetric zigzag-edged ribbon, the spin-polarization rate approaches -100% at electric field strength -0.2 V/A. Interestingly, an applied strain can transform a symmetric zigzag-carbon-edge ribbon from a magnetic semiconductor to a half-metal. And the half-metal property remains unchanged when the strain increases from 8 to 15%, while the spin-up subband gap further increases to 0.46 eV. These numerical results may be useful to engineer and design magnetic-field-free spintronic devices based on the 2D C3N. (C) 2018 Elsevier Ltd. All rights reserved.