title: Resonant Raman scattering of the smallest single-walled carbon nanotubes.
abstract: We report optical properties of the smallest single-walled carbon nanotubes (SWNTs) with a diameter of only 3 A. These ultrasmall SWNTs are fabricated in the elliptical nanochannels of an AlPO-11 (AEL) single crystal. Polarized and resonant Raman scattering unambiguously revealed that these 0.3 nm SWNTs are of (2,2) armchair symmetry. Interestingly, the (2,2) armchair tube has two metastable ground states corresponding to two slightly different lattice constants in the axial direction: one state is metallic and the other is semiconducting.
authors.affiliation: Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong. phzktang@ust.hk
authors.forename: Z K
authors.initials: ZK
authors.lastname: Tang
authors.forename: J P
authors.initials: JP
authors.lastname: Zhai
authors.forename: Y Y
authors.initials: YY
authors.lastname: Tong
authors.forename: X J
authors.initials: XJ
authors.lastname: Hu
authors.forename: R
authors.initials: R
authors.lastname: Saito
authors.forename: Y J
authors.initials: YJ
authors.lastname: Feng
authors.forename: Ping
authors.initials: P
authors.lastname: Sheng