Time-resolved impurity-invisibility in graphene nanoribbons
Abstract
We investigate time-resolved charge transport through graphene nanoribbons supplemented with adsorbed impurity atoms. Depending on the location of the impurities with respect to the hexagonal carbon lattice, the transport properties of the system may become invisible to the impurity due to the symmetry properties of the binding mechanism. This motivates a chemical sensing device since dopants affecting the underlying sublattice symmetry of the pristine graphene nanoribbon introduce scattering. Using the time-dependent Landauer--B{\"u}ttiker formalism, we extend the stationary current-voltage picture to the transient regime, where we observe how the impurity invisibility takes place at sub-picosecond time scales further motivating ultrafast sensor technology. We further characterize time-dependent local charge and current profiles within the nanoribbons, and we identify rearrangements of the current pathways through the nanoribbons due to the impurities. We finally study the behavior of the transients with ac driving which provides another way of identifying the lattice-symmetry breaking caused by the impurities.
Cite
@article{arxiv.1903.12538,
title = {Time-resolved impurity-invisibility in graphene nanoribbons},
author = {Riku Tuovinen and Michael A. Sentef and Claudia Gomes da Rocha and Mauro S. Ferreira},
journal= {arXiv preprint arXiv:1903.12538},
year = {2019}
}