Graphene kirigami as a platform for stretchable and tunable quantum dot arrays

TL;DR

This paper investigates how graphene kirigami structures can serve as tunable platforms for quantum dot arrays, revealing how elastic deformations influence quantum transport, miniband formation, and conductance properties.

Contribution

It introduces a theoretical analysis of quantum transport in graphene kirigami under elastic deformation, highlighting tunable miniband and stop-gap features linked to geometry and pseudomagnetic fields.

Findings

Conductance profiles mimic coupled quantum dot systems at low densities.

Elastic deformation stages alter conductance and I-V characteristics.

Negative differential conductance arises from miniband and stop-gap structures.

Abstract

The quantum transport properties of a graphene kirigami similar to those studied in recent experiments are calculated in the regime of elastic, reversible deformations. Our results show that, at low electronic densities, the conductance profile of such structures replicates that of a system of coupled quantum dots, characterized by a sequence of minibands and stop-gaps. The conductance and I-V curves have different characteristics in the distinct stages of elastic deformation that characterize the elongation of these structures. Notably, the effective coupling between localized states is strongly reduced in the small elongation stage, whereas in the large elongation regime the development of strong, localized pseudomagnetic field barriers can reinforce the coupling and reestablish resonant tunneling across the kirigami. This provides an interesting example of interplay between geometry and pseudomagnetic field-induced confinement. The alternating miniband and stop-gaps in the transmission lead to I-V characteristics with negative differential conductance in well defined energy/doping ranges. These effects should be stable in a realistic scenario that includes edge roughness and Coulomb interactions, as these are expected to further promote localization of states at low energies in narrow segments of graphene nanostructures.