Charge transport in charge-ordered states of two-dimensional organic conductors, α-(BEDT-TTF) 2I 3 and α'-(BEDT-TTF) 2IBr 2

Kota Kodama, Motoi Kimata, Yamaguchi Takahide, Nobuyuki Kurita, Atsushi Harada, Hidetaka Satsukawa, Taichi Terashima, Shinya Uji, Kaoru Yamamoto, Kyuya Yakushi

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11 Citations (Scopus)

Abstract

Electric conductance and dielectric constant have been measured in the charge-ordered states of the quasi two-dimensional organic conductors α-(BEDT-TTF) 2I 3 and α'-(BEDT-TTF) 2IBr 2 to understand the charge transport mechanism. The current-voltage (I-V) characteristics show a strong nonlinear behavior, which is qualitatively explained by the transport of individual carriers thermally excited from the charge-ordered states in BEDT-TTF layers. The discrepancy with the simulation based on the thermal activation model at low temperatures is likely due to quantum tunneling through the potential barrier. The dielectric constants show a large difference between the in-plane and out-of-plane directions of the samples, showing a highly two-dimensional nature of Coulomb potential. The temperature dependence of dielectric constant is ascribed to the polarization effect of the thermally excited electronhole pairs, consistent with the model of nonlinear I-V characteristics. All these features are qualitatively the same between α-(BEDT-TTF) 2I 3 and α'-(BEDT-TTF) 2IBr 2, despite the different structural and magnetic properties.

Original languageEnglish
Article number044703
Journaljournal of the physical society of japan
Volume81
Issue number4
DOIs
Publication statusPublished - 2012 Apr 1
Externally publishedYes

Keywords

  • Charge ordering
  • Dielectric property
  • Low-dimensional system
  • Nonlinear I-V characteristics
  • Organic conductor
  • Strongly correlated electron system

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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    Kodama, K., Kimata, M., Takahide, Y., Kurita, N., Harada, A., Satsukawa, H., Terashima, T., Uji, S., Yamamoto, K., & Yakushi, K. (2012). Charge transport in charge-ordered states of two-dimensional organic conductors, α-(BEDT-TTF) 2I 3 and α'-(BEDT-TTF) 2IBr 2 journal of the physical society of japan, 81(4), [044703]. https://doi.org/10.1143/JPSJ.81.044703