METALLIC RESISTIVITY IN CRYSTALLINE ROPES OF SINGLE-WALL CARBON NANOTUBES

Laser ablation of (Co,Ni)-doped graphite yields similar to 70% single- wall nanotubes, predominantly (10,10) armchair tubes which self-organi ze into crystalline ''ropes''>100 Angstrom in diameter and>10 mu m lon g. We find rho(parallel to)=0.03-0.10 m Omega cm at 300 K, with positi ve (negative) d rho/dT above (below) T = 35 K. Unoriented bulk sample s exhibit similar behavior, with higher (directionally averaged) resis tivities and T's. The high-T behavior is consistent with the predicte d intrinsic metallic state for this structure.