Ultrafast IR and THz spectroscopy of photo-induced insulator to metal transition in highly correlated organic system

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3 Citations (Scopus)

Abstract

Photo-induced insulator to metal transitions (PIMT) in quarter filled layered organic conductors ET [bis(ethylenedithio)tetrathiafulvalene]-based salts α-(ET)2I3, θ-(ET)2RbZn(SCN) 4, and κ-(d-ET)2Cu[N(CN)2Br] were investigated using ultrafast spectroscopy in the near, mid-infrared and terahertz (THz) regions. In charge ordered salts α-(ET)2I 3 and θ-(ET)2RbZn(SCN)4, an immediate (<30 fs) generation of a microscopic metallic state is driven by the electronic process. Subsequently, condensation of the microscopic metallic domain to the macroscopic scale is accompanied by a small molecular rearrangement in α-(ET)2I3. However, in θ-(ET)2RbZn(SCN)4, a large structural difference between the insulator and metallic phases prevents stabilization of the macroscopic metallic state. In a dimer Mott insulator κ-(d-ET) 2Cu[N(CN)2Br], photo-generation of the metallic state shows a finite rise time of ca. 1 ps, which is attributable to the photo-induced change of on-site Coulomb energy on each dimer (Udim) through dimeric molecular rearrangement. Thus, the ultrafast dynamics of PIMT depend strongly on the molecular arrangement in the layer of ET salts.

Original languageEnglish
Pages (from-to)409-414
Number of pages6
JournalJournal of Luminescence
Volume131
Issue number3
DOIs
Publication statusPublished - 2011 Mar 1

Keywords

  • Charge order
  • Correlated electron system
  • Mott insulator
  • Organic conductor
  • Photo-induced phase transition
  • Ultarfast spectroscopy

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Chemistry(all)
  • Biochemistry
  • Biophysics

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