Abstract
The central question in the field of 2D materials is how a material behaves when it is patterned at nanometer scale with different edge geometries. Due to the anisotropy inherent in the puckered structure, black phosphorene nanostructures may have more varieties of edge geometries. Here, we present a comprehensive 2D planar crystallographic characterization of phosphorene uniformly by a chiral vector (angle), from which a new type of edge atomic configuration, the slope edge geometry is discovered. The phosphorene nanoribbons (PNRs) with slope edges, like previously noticed zigzag and skewed-armchair PNRs, also own interesting twofold-degenerate edge states. These three marginal directions, together with the skewed-zigzag and armchair directions without edge states, divide a phosphorene into four regions among which the electronic property is different from each other. Further, for a PNR cutting along any possible direction, by taking into account the z-direction in structure, whether or not it owns edge states depends on the periodic zigzag-like morphology along the edges. Moreover, we propose a PNR-based z-shaped homogenous junction with scale $\sim$100 nm, where the central scattering region between two PNR electrodes is a phosphorene quantum dot (PQD) of PNR segment with various edge morphologies. Interestingly, the calculated conductance of the junction relies sensitively on the central PQD edge states, which exhibits a terrace with resonant oscillations near Fermi energy, otherwise the electron transport is blocked due to the absence of edge states. Remarkably, the number of oscillating peaks exactly matches to the number of sawtooth along an edge of PQD, since the discrete energy levels of the zigzag-like edge provide the transporting channels for electrons. The results here may be extended to the group-VA 2D materials for observing the electronic property of nanostructures.
Highlights
In the current decade, two-dimensional (2D) materials have emerged as one of the most exciting classes of materials since the rise of graphene [1]
By taking into account the effect of the z direction in the structure, we demonstrate the variation of the electronic properties for phosphorene nanoribbons (PNRs) with different edge atomic geometries by the KWANT code based on tight-binding (TB) calculations [48], in which particular attention is paid to the SLPNR, which intrinsically has twofold-degenerate edge states
This is similar to the band structure of (3,1)nbPNR, but the bulk band and its position relating to the edge state are still significantly different
Summary
Two-dimensional (2D) materials have emerged as one of the most exciting classes of materials since the rise of graphene [1]. The electronic properties are significantly different from each other among PNRs with different chiralities This difference results in an abundant electrical nature, such as metals with edge states and semiconductors with a direct band gap. By taking into account the effect of the z direction in the structure, we demonstrate the variation of the electronic properties for PNRs with different edge atomic geometries by the KWANT code based on tight-binding (TB) calculations [48], in which particular attention is paid to the SLPNR, which intrinsically has twofold-degenerate edge states.
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call