Tunable transmission due to defects in zigzag phosphorene nanoribbons

TL;DR

This paper analytically investigates how defects affect electron transport in zigzag phosphorene nanoribbons, revealing tunable conductance resonances and shielding effects that could influence nanoelectronic device design.

Contribution

It provides a detailed analytical study of defect-induced conductance modulation in phosphorene nanoribbons, including novel shielding phenomena caused by vacancy placement.

Findings

Resonant conductance peaks occur with edge defects at specific energies.

Second vacancy can create a shielding region that enhances conductance.

Analytical results agree well with numerical simulations.

Abstract

Transport of the edge-state electrons along zigzag phosphorene nanoribbons in presence of two impurities/vacancies is analytically investigated. Considering the places of the defects, a number of different situations are examined. When both defects are placed on the edge zigzag chain, as is expected, with changing the energy of the traveling electrons the electrical conductance exhibits a resonance behavior. In this case, for two vacancies the observed resonant peaks become extremely sharp. An amazing behavior is seen when the second vacancy is located along an armchair chain while the first is placed at the intersection of the edge zigzag and this armchair chains. In this case, in a considerable range of energy, the conductance is strongly strengthened. In fact the presence of the second vacancy create a shielded region around the first vacancy, consequently, the traveling wave bypasses this region and enhances the conductivity. The analytical results are compared with numerical simulations showing a very good agreement.