Quantum transport in honeycomb lattice ribbons with zigzag edges: A theoretical study

TL;DR

This theoretical study investigates electron transport in honeycomb lattice ribbons with zigzag edges, revealing persistent energy gaps and semiconducting behavior that vary with ribbon size.

Contribution

The paper provides a detailed theoretical analysis of transport properties in zigzag-edged honeycomb ribbons, highlighting the persistent energy gap and size-dependent conductance.

Findings

Energy gap always appears at E=0 in conductance spectrum.

Gap decreases with increasing ribbon size but never vanishes.

Ribbons exhibit semiconducting behavior, confirmed by I-V characteristics.

Abstract

We explore electron transport properties in honeycomb lattice ribbons with zigzag edges coupled to two semi-infinite one-dimensional metallic electrodes. The calculations are based on the tight-binding model and the Green's function method, which numerically compute the conductance-energy and current-voltage characteristics as functions of the lengths and widths of the ribbons. Our numerical results predict that for such a ribbon an energy gap always appears in the conductance spectrum across the energy E=0. With the increase of the size of the ribbon, the gap gradually decreases but it never vanishes. This clearly manifests that a honeycomb lattice ribbon with zigzag edges always exhibits the semiconducting behavior, and it becomes much more clearly visible from our presented current-voltage characteristics.