F Guyton | Searcharxiv

arXiv2018

Spectral approach to transport in the 2D honeycomb lattice with substitutional disorder

The transport properties of a disordered two-dimensional (2D) honeycomb lattice are examined numerically using the spectral approach to the quantum percolation problem, characterized by an Anderson-type Hamiltonian. In our simulations, substitutional disorder (or doping) is represented by a modified bimodal probability distribution of the on-site energies. The results indicate the existence of extended energy states for nonzero disorder and the emergence of a transition towards localized behavior for critical doping concentration n_D>0.3%, in agreement with the experimentally observed metal-to-insulator transition in graphene sheet doped with hydrogen.

physics.comp-ph↗

arXiv2018

Transport properties of disordered 2D complex plasma crystal

In this work, we investigate numerically the transport properties of a 2D complex plasma crystal using diffusion of coplanar dust lattice waves. In the limit where the Hamiltonian interactions can be decoupled from the non-Hamiltonian effects, we identify two distinct types of wave transport: Anderson-type delocalization and long-distance excitation. We use a recently-developed spectral approach to evaluate the contribution of the Anderson problem and compare it to the results of the simulation. The benefit of our approach to transport problems is twofold. First, we employ a highly tunable macroscopic hexagonal crystal, which exhibits many-body interactions and allows for the investigation of transport properties at the kinetic level. Second, the analysis of the transport problem in 2D is provided using an innovative spectral approach, which avoids the use of scaling and boundary conditions. Thus, the combination of theoretical calculation with simulation results allows for the study of important characteristics of this open system. The major deviation between the predicted and observed wave dynamics is a long-distance lattice excitation, which occurs even when the initial perturbation does not spread from the center to the exterior of the crystal. In the decoupled Hamiltonian regime, this effect can be contributed to the dust lattice interaction with the plasma environment.

physics.plasm-ph↗