Computer simulation of scanning tunneling spectroscopy of supported carbon nanotube aggregates

摘要

Among the various techniques to investigate carbon nanotubes scanning tunneling microscopy (STM) is one of the most promising since it gives access to both the atomic and electronic structures (STS). The interpretation of the experimental data remains delicate, however. We performed dynamical quantum-mechanical calculations aimed at understanding what controls the current-voltage characteristics in the STM investigation of different arrangements of nanotubes. The calculated STS spectra are directly comparable to experimental data. The theory allowed us to identify one component of pure geometrical origin responsible for an asymmetry of I-V curve, as often observed experimentally above a carbon nanotube. It is emphasized that this asymmetry strongly depends on the shape of the tip, and this may change during the experiment.