title: Temperature dependence of the band gap of semiconducting carbon nanotubes.
abstract: The temperature dependence of the band gap of semiconducting single-wall carbon nanotubes (SWNTs) is calculated by direct evaluation of electron-phonon couplings within a "frozen-phonon" scheme. An interesting diameter and chirality dependence of E(g)(T) is obtained, including nonmonotonic behavior for certain tubes and distinct "family" behavior. These results are traced to a strong and complex coupling between band-edge states and the lowest-energy optical phonon modes in SWNTs. The E(g)(T) curves are modeled by an analytic function with diameter- and chirality-dependent parameters; these provide a valuable guide for systematic estimates of E(g)(T) for any given SWNT. The magnitudes of the temperature shifts at 300 K are smaller than 12 meV and should not affect (n,m) assignments based on optical measurements.
authors.affiliation: Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, Rio de Janeiro, RJ 21941-972, Brazil.
authors.forename: Rodrigo B
authors.initials: RB
authors.lastname: Capaz
authors.forename: Catalin D
authors.initials: CD
authors.lastname: Spataru
authors.forename: Paul
authors.initials: P
authors.lastname: Tangney
authors.forename: Marvin L
authors.initials: ML
authors.lastname: Cohen
authors.forename: Steven G
authors.initials: SG
authors.lastname: Louie