Image-potential states of single- and multiwalled carbon nanotubes

Abstract

The existence of low angular momentum image-potential states is predicted both for single-and multiwalled nanotubes. The states are confined between the self-induced potential on the vacuum side and the surface barrier, created by the central ascent in the transverse nanotube potential. Effective interactions near the surface of the nanotube are modeled with a cylindrical jelliumlike surface barrier, parameterized to ensure the correct transition into the long-range image potential. Binding energies and wave functions are calculated for (12,0), (10,10), (9,0) single-walled and ͑d = 9.48 nm͒ multiwalled nanotubes for different values of electron angular momenta. In addition, the expected relative lifetimes were calculated for the case of zero-angular momentum states of a (10,10) SWNT. The possible formation of image-potential states in nanotube bundles is briefly discussed.

Image potential states in graphene

“…When graphene layers are assembled into a graphite crystal, the interlayer band can be viewed as a consequence of trapping and hybridization of the lowest-energy 1 + image-potential state. Moreover, the unoccupied electronic states in other carbon-based nanostructures, like fullerenes, 15 fullerites, 14 and nanotubes [34][35][36] can be understood as having the common origin with the graphene image-potential states found in the present work. A large extent of wave functions of the imagepotential states in the vacuum implies that they are very sensitive to any change of shape or/and environment of the graphene sheet.…”

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

“…For a strong centrifugal repulsion associated with high values of electron angular momenta, single wall carbon nanotubes (SWNT) were predicted to support the tubular image states that form in the potential well between the repulsive barrier and the long-range image-interaction [16]. On the other hand, our recent study [17] has suggested that in addition to tubular image states, both single and multiwalled carbon nanotubes can support low-and zero-angular momentum image states with weak transverse penetrations into the bulk (see Fig. 1).…”

Hybrid image potential states in molecular overlayers on graphene

“…More exotic IPSs appear on curved graphene, typical examples of which are tubular IPSs extended around carbon nanotubes [5] and superatom molecular orbitals of C 60 fullerene [6]. The hybridization of these IPSs results in the interlayer states with a nearly-free-electron feature in a variety of graphitic materials such as graphite [3], multiwalled [7,8] or bundles [9,10] of carbon nanotubes, fullerite solids [11,12], and carbon nanopeapods [13]. In particular, the interlayer states in graphite are believed to be crucial for the superconductivity of graphiteintercalation compounds [14].…”