We theoretically investigate phosphorene zigzag nanorribons as a platform for
constriction engineering. In the presence of a constriction at the upper edge,
quantum confinement of edge protected states reveals resonant tunnelling
Breit-Wigner transmission peaks, if the upper edge is uncoupled to the lower
edge. Coupling between edges in thin constrictions gives rise to Fano-like and
anti-resonances in the transmission spectrum of the system.Comment: 8 pages,7 figure