Environmental influence on linear optical spectra and relaxation dynamics in carbon nanotubes

Abstract

AbstractWe present theoretical investigations on linear optical spectra and the temporal non‐equilibrium dynamics of single‐walled carbon nanotubes. In particular we discuss the importance of the surrounding medium. Our approach is based on the density matrix theory, which in combination with tight‐binding wave functions allows the calculation of linear and nonlinear optical properties of arbitrary nanotubes. Its strength lies in the straightforward way to describe non‐equilibrium properties, such as Coulomb driven ultrafast intrasubband carrier relaxation. We find a strong influence of the surrounding dielectric medium on the position of the peaks, the excitonic binding energy, and the carrier relaxation time. Furthermore, simple scaling laws describing the dependence on the dielectric background constant $\varepsilon _{{\rm bg}}$ are shown.