Anomalous dielectric response in the π-d correlated metallic state of λ-(BEDT-TSF)2FeCl4

Hiroshi Matsui, Hideaki Tsuchiya, Eiichi Negishi, Hiroshi Uozaki, Yusuke Ishizaki, Yasunori Abe, Satoshi Endo, Naoki Toyota

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37 Citations (Scopus)


The temperature dependence of the microwave conductivity σ1 and dielectric constant ∈1 has been measured on λ-(BEDT-TSF)2FeCl4 by a cavity perturbation method at 16.3 GHz, employing the TE011 resonant mode. In spite of the highly metallic state; above the metal-to-insulator (MI) transition at TMI = 8.3 K, a novel ferroelectric-like response is observed in ∈lc along c at high temperatures from TMI to TFM = 70 K, which is enhanced to the order of 103 just above TMI. Then a transition from a ferroelectric-like to paraelectric-like state with ∈lc ∼ 45 takes part in the MI transition. In contrast to the dc conductivity, σlc becomes much more conductive as considered by a collective mode. The ferroelectric-like response is associated with the dynamical response of the charge degrees of freedom in the π electronic system. An absence of these dielectric and thermodynamical anomalies in the nonmagnetic Ga analogue indicates the importance of the π-d interaction for the ferroelectric-like state as well as the MI transition.

Original languageEnglish
Pages (from-to)2501-2504
Number of pages4
Journaljournal of the physical society of japan
Issue number9
Publication statusPublished - 2001 Sept


  • Charge disproportionation
  • Collective mode
  • Conductivity
  • Dielectric function
  • Metal-to-insulator transition
  • Microwave
  • λ-(BEDT-TSF)FeCl
  • π-d interaction

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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