Novel pressure-induced 2κF CDW state in organic low-dimensional compound θ-(BEDT-TTF)2CsCo(SCN)4

Masashi Watanabe, Yoshio Nogami, Kokichi Oshima, Hatsumi Mori, Shoji Tanaka

Research output: Contribution to journalArticle

70 Citations (Scopus)

Abstract

A band structure calculation based on the X-ray structure analysis reveals that pressure raises quasi one-dimensionality of the Fermi surface of the title compound. A 2κF lattice modulation is observed with a wave vector q′2 = (2/3 0 0.29) at 10.7 kbar and room temperature. This is the first observation of pressure-induced CDW. With cooling, the wave vector of the modulation changes from q′3 to commensurate q3 = (2/3 0 1/3) below 240 K. On the other hand, at ambient pressure and 20 K where the resistivity begins to increase rapidly, three-dimensional short range ordering occurs for the weak diffuse spot with a wave vector q2 = (0 0 1/2). This modulation is ascribable to an occurrence of charge ordering possibly caused by the nearest neighbor Coulomb interaction V. A schematic phase diagram for the electronic state is presented.

Original languageEnglish
Pages (from-to)2654-2663
Number of pages10
Journaljournal of the physical society of japan
Volume68
Issue number8
DOIs
Publication statusPublished - 1999 Aug

Keywords

  • BEDT-TTF
  • CDW
  • Charge ordering
  • Low-dimensional conductors
  • Pressure
  • Structural change
  • X-ray, crystal structure

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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