title: Gapping by squashing: metal-insulator and insulator-metal transitions in collapsed carbon nanotubes
abstract: Squashing brings circumferentially separated areas of a carbon nanotube into close proximity, drastically altering the low-energy electronic properties and (in some cases) reversing standard rules for metallic versus semiconducting behavior. Such a deformation mode, not requiring motion of tube ends, may be useful for devices. Uniaxial stress of a few kbar can reversibly collapse a small-radius tube, inducing a 0.1 eV gap with a very strong pressure dependence, while the collapsed state of a larger tube is stable. The low-energy electronic properties of chiral tubes are surprisingly insensitive to collapse.
authors.affiliation: Department of Physics and Center for Materials Physics, The Pennsylvania State University, 104 Davey Lab, University Park, Pennsylvania 16802, USA.
authors.initials: PE
authors.lastname: Lammert
authors.initials: P
authors.lastname: Zhang
authors.initials: VH
authors.lastname: Crespi