Electromechanical responses of single-walled carbon nanotubes: Interplay between the strain-induced energy-gap opening and the pinning of the Fermi level

A comprehensive picture of electromechanical responses of carbon single-walled nanotubes SWNTs is obtained using ab initio density-functional theory and self-consistent -orbital Hamiltonian. We find a linear behavior of the energy gap of zigzag SWNTs as a function of the axial strain with different slopes for compression versus extension. Observed small changes in conductance even with a substantial energy gap due to the strain is attributed to the pinning of the Fermi level near the top of the valence band. © 2005 American Institute of Physics. DOI: 10.1063/1.2011781