title: Conducting linear chains of sulphur inside carbon nanotubes.
abstract: Despite extensive research for more than 200 years, the experimental isolation of monatomic sulphur chains, which are believed to exhibit a conducting character, has eluded scientists. Here we report the synthesis of a previously unobserved composite material of elemental sulphur, consisting of monatomic chains stabilized in the constraining volume of a carbon nanotube. This one-dimensional phase is confirmed by high-resolution transmission electron microscopy and synchrotron X-ray diffraction. Interestingly, these one-dimensional sulphur chains exhibit long domain sizes of up to 160 nm and high thermal stability (~800 K). Synchrotron X-ray diffraction shows a sharp structural transition of the one-dimensional sulphur occurring at ~450-650 K. Our observations, and corresponding electronic structure and quantum transport calculations, indicate the conducting character of the one-dimensional sulphur chains under ambient pressure. This is in stark contrast to bulk sulphur that needs ultrahigh pressures exceeding ~90 GPa to become metallic.
authors.affiliation: Research Center for Exotic Nanocarbons (JST), Shinshu University, 4-17-1 Wakasato, Nagano 380-8553, Japan. t_fujimori@shinshu-u.ac.jp
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Fujimori
authors.forename: Aarón
authors.initials: A
authors.lastname: Morelos-Gómez
authors.forename: Zhen
authors.initials: Z
authors.lastname: Zhu
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Muramatsu
authors.forename: Ryusuke
authors.initials: R
authors.lastname: Futamura
authors.forename: Koki
authors.initials: K
authors.lastname: Urita
authors.forename: Mauricio
authors.initials: M
authors.lastname: Terrones
authors.forename: Takuya
authors.initials: T
authors.lastname: Hayashi
authors.forename: Morinobu
authors.initials: M
authors.lastname: Endo
authors.forename: Sang Young
authors.initials: SY
authors.lastname: Hong
authors.forename: Young Chul
authors.initials: YC
authors.lastname: Choi
authors.forename: David
authors.initials: D
authors.lastname: Tománek
authors.forename: Katsumi
authors.initials: K
authors.lastname: Kaneko