Time-Resolved Photoimaging of Image-Potential States in Carbon Nanotubes

Abstract

The first experimental evidence for the existence of image-potential states in carbon nanotubes is presented. The observed features constitute a new class of surface image states due to their quantized centrifugal motion. Measurements of binding energies and the temporal evolution of image state electrons were performed using femtosecond time-resolved photoemission. The associated lifetimes are found to be significantly longer than those of n=1 image state on graphite, indicating a substantial difference in electron decay dynamics between tubular and planar graphene sheets.

Probing quantized image-potential states at supported carbon nanotubes

“…It can be seen that ISs are already formed at distances of the order of 1 nm away from the surface of the supported nanotube. These distances are similar to the radii of localization for low-and zero-angular momentum ISs formed at unsupported nanotubes [19,20]. The ISs can be discerned more clearly in figure 1 (bottom), where we present the derivative dz/dV (V ) of the z(V ) spectrum in figure 1 (top).…”

Correlated Diskoid-like Electronic States

“…Similar extended electronic states were predicted to form91011 and observed1213 above the surfaces of metallic carbon nanotubes (CNT). In these tubular image state (TIS), the electron is attracted to its hole image formed on a highly (longitudinally) polarizable CNT surface.…”

Strongly Localized Image States of Spherical Graphitic Particles

“…Experimental work [11] includes photoionization [12] and time-resolved photoimaging of image-potential states in carbon nanotubes [13]. There has been general interest [14] in these structures because of electronic control on the nanoscale using image states.…”