Controlling disorder in two-dimensional networks

Abstract

Two-dimensional networks are constructed by reference to a distribution of ring sizes and a parameter (α) which controls the preferred nearest-neighbour spatial correlations, and allows network topologies to be varied in a systematic manner. Our method efficiently utilizes the dual lattice and allows the range of physically-realisable configurations to be established and compared to networks observed for a wide range of real and model systems. Three different ring distributions are considered; a system containing five-, six- and seven-membered rings only (a proxy for amorphous graphene), the configuration proposed by Zachariasen in 1932, and a configuration observed experimentally for thin (near-2D) films of SiO2. The system energies are investigated as a function of the network topologies and the range of physically-realisable structures established and compared to known experimental results. The limits on the parameter α are discussed and compared to previous results. The evolution of the network structure as a function of topology is discussed in terms of the ring-ring pair distribution functions.