From adiabatic to non-adiabatic pumping in graphene nanoribbons

TL;DR

This paper investigates how quantum pumping in graphene nanoribbons transitions from adiabatic to non-adiabatic regimes, revealing the role of edge states and mode interactions in transport properties.

Contribution

It provides a detailed analysis of the crossover between adiabatic and non-adiabatic pumping in graphene ribbons using a tight-binding model and Keldysh formalism, highlighting the influence of edge states.

Findings

Pumped dc currents in armchair ribbons exhibit properties similar to 2D systems.

Edge states in zigzag ribbons do not contribute to adiabatic pumped transport.

The interplay between propagating and evanescent modes affects transport behavior.

Abstract

Non-equilibrium two-parameter pumping transport through graphene ribbons, attached to reservoirs is described. A tight-binding model is solved using Keldysh formalism, and the crossover between adiabatic and non-adiabatic regimes is studied. Pumped dc currents through armchair ribbons show properties common in two-dimensional systems. The width-dependent dc current in zigzag ribbons, reveals that edge states akin to those in two-dimensional topological insulators, do not contribute to pumped transport in the adiabatic regime. The interplay between propagating and evanescent modes is discussed.