Collective charge excitation in a dimer mott insulating system

Makoto Naka, Sumio Ishihara

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28 Citations (Scopus)


Charge dynamics in a dimer Mott insulating system, where a nonpolar dimer-Mott (DM) phase and a polar chargeordered (CO) phase compete with each other, are studied. In particular, collective charge excitations are analyzed in three different models where the internal degree of freedom in a dimer is taken into account. Collective charge excitation exists in both the nonpolar DM and polar CO phases, and softens in the phase boundary. This mode is observable in the optical conductivity spectra when light polarization is parallel to the electric polarization in the polar CO phase. Connections between the present theory and the recent experimental results for κ-(BEDT-TTF) 2Cu2(CN)3 are discussed.

Original languageEnglish
Article number023701
Journaljournal of the physical society of japan
Issue number2
Publication statusPublished - 2013 Feb


  • Charge order
  • Collective mode
  • Dimer-Mott insulator
  • Ferroelectricity
  • Optical conductivity

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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