Modeling STM images of chiral metallic carbon nanotubes

Abstract

Scanning tunneling microscopy is a powerful tool for the study of the electronic and structural properties of carbon nanotubes. Efforts have been made to image discrete states on short metallic nanotubes. Here we address two important issues pertinent to understanding such images. (1) Electronic states of nanotubes have two bands at the Fermi energy. Reflection at the end of the tube will mix the bands in a non-universal way to form two distinct families of eigenstates. (2) Images of graphite and nanotubes can be drastically altered by asymmetries in the STM tip. We consider these images for finite chiral metallic tubes and demonstrate that by using both classes of image the tip effect can be extracted from the image. In this way the tip asymmetry can be quantified, and the eigenstates on the tube can be seen.