Impossibility of superconducting state in multiwall carbon nanotubes and single crystal graphite

The magnetic susceptibility chi as of pristine and brominated arc-produced sample of multiwall carbon,nanotubes (MWNTs) so single-crystal graphite (SCG) was measured from 4.5 to 400 K. An additional contribution Deltachi(T) to diamagnetic susceptibility chi(T) of carbon materials was found at T < 50 K for all samples. It is shown that Deltachi(T) are dominated by quantum correction to chi for interaction electrons (interaction effects, IE). The IE shows a crossover from two-dimensional to three-dimensional at B = 5.5 T for MWNTs and always three-dimensional for SCG. The effective interaction between electrons for interior layers as MWNTs so SCG are repulsion and the electron-electron interaction A, was estimated to be lambda(c) similar to 0.26 for MWNTs and lambda(c) similar to 0.06 for SCG. (C) 2003 Elsevier Science B.V. All rights reserved.