Mechanism behind the switching of current induced by a gate field in a semiconducting nanowire junction

TL;DR

This paper introduces an orbital-controlled model to explain how gate fields induce current switching in semiconducting nanowire junctions, revealing the role of orbital mixing and delocalization in conductance changes.

Contribution

The study presents a new orbital-based model combined with a density functional approach to explain gate-induced current switching in lead-chalcogenide nanowires.

Findings

Orbital mixing occurs after a threshold gate voltage.

Delocalization along the channel increases conductance.

The model applies to both PbS and PbSe nanowires.

Abstract

We propose a new orbital controlled model to explain the gate field induced switching of current in a semiconducting PbS-nanowire junction. A single particle scattering formalism in conjunction with a posteriori density functional approach involving hybrid functional is used to study the electronic current; both first and higher order Stark effects are explicitly treated in our model. Our calculation reveals that after a threshold gate-voltage, orbital mixing produces p-components at the S atoms in the participating orbitals. This results in an inter-layer orbital interaction that allows electron to delocalize along the channel axis. As a consequence a higher conductance state is found. A similar feature is also found in a PbSe nanowire junction, which suggests that this model can be used universally to explain the gate field induced switching of current in lead-chalcogenide nanowire junctions.