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

The magnetic susceptibility χ 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 Δχ(T) to diamagnetic susceptibility χ(T) of carbon materials was found at T<50 K for all samples. It is shown that Δχ(T) are dominated by quantum correction to χ 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 λc was estimated to be λc∼0.26 for MWNTs and λc∼0.06 for SCG