Site-percolation threshold of carbon nanotube fibers—Fast inspection of percolation with Markov stochastic theory

• A modified FCC lattice model to simulate close-packed carbon nanotube bundles.
• A new and fast Markov-theory-based approach to inspect percolation.
• We obtain the lower bound of percolation threshold for a regular CNT bundle.
• The dependence of percolation threshold on the geometry of CNT bundle.

We present a site-percolation model based on a modified FCC lattice, as well as an efficient algorithm of inspecting percolation which takes advantage of the Markov stochastic theory, in order to study the percolation threshold of carbon nanotube (CNT) fibers. Our Markov-chain based algorithm carries out the inspection of percolation by performing repeated sparse matrix–vector multiplications, which allows parallelized computation to accelerate the inspection for a given configuration. With this approach, we determine that the site-percolation transition of CNT fibers occurs at pc=0.1533±0.0013pc=0.1533±0.0013, and analyze the dependence of the effective percolation threshold (corresponding to 0.5 percolation probability) on the length and the aspect ratio of a CNT fiber on a finite-size-scaling basis. We also discuss the aspect ratio dependence of percolation probability with various values of pp (not restricted to pcpc).