Electric Field Tunable Topological Phases in Graphene Nanoribbons

TL;DR

This paper demonstrates that applying a transverse electric field to doped graphene nanoribbons can controllably switch their topological phases, enabling programmable topological junctions for quantum electronic applications.

Contribution

It reveals that electric fields can tune topological phases in doped GNRs via band inversion, offering a new method for designing GNR-based quantum devices.

Findings

Electric field induces topological phase transitions in doped GNRs.

Spatially varying fields create programmable topological junctions.

Topological phases can be controlled for quantum device applications.

Abstract

Graphene nanoribbons (GNRs) possess distinct symmetry-protected topological phases. We show, through first-principles calculations, that by applying an experimentally accessible transverse electric field (TEF), certain boron and nitrogen periodically co-doped GNRs have tunable topological phases. The tunability arises from a field-induced band inversion due to an opposite response of the conduction- and valance-band states to the electric field. With a spatially-varying applied field, segments of GNRs of distinct topological phases are created, resulting in a field-programmable array of topological junction states, each may be occupied with charge or spin. Our findings not only show that electric field may be used as an easy tuning knob for topological phases in quasi-one-dimensional systems, but also provide new design principles for future GNR-based quantum electronic devices through their topological characters.