Interplay of electron-electron and electron-phonon interactions in the low-temperature phase of 1T-TaS2

Doohee Cho, Yong Heum Cho, Sang Wook Cheong, Ki Seok Kim, Han Woong Yeom

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24 Citations (Scopus)

Abstract

We investigate the interplay of the electron-electron and electron-phonon interactions in the electronic structure of an exotic insulating state in the layered dichalcogenide 1T-TaS2, where the charge-density-wave (CDW) order coexists with a Mott correlation gap. Scanning tunneling microscopy and spectroscopy measurements with high spatial and energy resolution determine unambiguously the CDW and the Mott gap as 0.20-0.24 eV and 0.32 eV, respectively, through the real space electron phases measured across the multiply formed energy gaps. An unusual local reduction of the Mott gap is observed on the defect site, which indicates the renormalization of the on-site Coulomb interaction by the electron-phonon coupling as predicted by the Hubbard-Holstein model. The Mott-gap renormalization provides insight into the disorder-induced quasimetallic phases of 1T-TaS2.

Original languageEnglish
Article number085132
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume92
Issue number8
DOIs
Publication statusPublished - 2015 Aug 18

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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