Strain-induced effects in zigzag-edged blue phosphorene nanoribbons with edge sulfur passivation

Motivated by the recent successful growth of quasi-free-standing single layer blue phosphorus (BlueP) on tellurium functionalized Au(1 1 1) by using black phosphorus as the precursor (Zhang et al 2016 Nano Lett. 16 4903; Gu et al 2017 ACS Nano 11 4943), here we study the strain performance for zigzag BlueP nanoribbons (zBluePNRs) with different edge chemical modifications. Based on the first-principles calculations, interestingly, we find that a narrow zBluePNR of width up to  ∼2 nm with edge sulfur (S) passivation under an uniaxial strain exhibits an important effect of negative Poisson's ratio because of the particularity of the P-S bonds at edges, and as the ribbon width further increases the Poisson's ratio varies from negative to positive. Meanwhile, the S-passivation also induces magnetism, and applying a strong enough strain can transfer this zBluePNR from magnetic metal state to half-metal one. All these physical properties are discussed in connection with the variation of microstructure of the ribbons. Our findings may paving the way for both a fundamental understanding of nanoscale physics and applied device engineering.