title: Current-voltage characteristics of charge-ordered organic crystals.
abstract: The current-voltage characteristics of layered organic crystals theta-(BEDT-TTF)2MZn(SCN)4 (M = Cs, Rb) follow the power law with a large exponent (e.g., 8.4 at 0.29 K for M = Cs) over a wide range of currents in the low-temperature insulating state. The power-law characteristics are attributed to electric field-induced unbinding of electron-hole pairs that are thermally excited in the background of the two-dimensional charge order. The magnitude of crossover electric fields from Ohmic to the power-law characteristics indicates that the electron-electron Coulomb interaction is significantly long-ranged: The screening length is greater than 10 molecule sites.
authors.affiliation: National Institute for Materials Science, Tsukuba 305-0003, Japan.
authors.forename: Yamaguchi
authors.initials: Y
authors.lastname: Takahide
authors.forename: Takako
authors.initials: T
authors.lastname: Konoike
authors.forename: Kengo
authors.initials: K
authors.lastname: Enomoto
authors.forename: Mitsuka
authors.initials: M
authors.lastname: Nishimura
authors.forename: Taichi
authors.initials: T
authors.lastname: Terashima
authors.forename: Shinya
authors.initials: S
authors.lastname: Uji
authors.forename: Hiroshi M
authors.initials: HM
authors.lastname: Yamamoto