First-principles investigation of carbon nanotube capacitance

With ab initio simulations based on a real-space nonequilibrium Green's function formalism, we have investigated the charging of carbon nanotube systems. The charging effects are described by capacitance coefficients, for which we provide a first-principles estimate. Specifically, the capacitance matrix of nested armchair nanotubes, the insertion of one nanotube into another, and a junction of two metallic nanotubes with a large conductance gap were calculated with a focus on investigating the bias-induced charges. For the case of the nanotube junction, the numerical value of the capacitance is sufficiently high, as to be useful for future device applications.