摘要
The emergency of superconductivity at the edge of charge density wave(CDW)state by pressure or chemical doping in 1T transition metal dichalcogenides(TMDs)has attracted much attention in past decade[1,2].The interplay of CDW and superconductivity has triggered the hot debate:why does superconductivity arise after suppressing the CDW and what’s the driving force
The emergency of superconductivity at the edge of charge density wave （CDW） state by pressure or chemical doping in 1T transi- tion metal dichalcogenides （TMDs） has attracted much attention in past decade [1, 2]. The interplay of CDW and superconduc- tivity has triggered the hot debate： why does superconductivity arise after suppressing the CDW and what＇s the driving force of the charge modulation？ For the 5d transition metal ditelluride IrTe2, a layered compound with trigonal symmetry, previous studies have shown an ordered superstructure below ～ 280 K, and a superconducting state when doped or intercalated with Pd or Pt [3, 4]. In IrTe2, the Fermi surface nesting has been excluded as the impetus of superstructure; instead, splitting of Te orbitals by the crystal field [5] or destabilization of polymeric Te-Te networks was proposed [6], evident from the visualized periodic dimer- ization of Te atoms by scanning tunneling microscopy （STM） [7]. Meanwhile, a charge disproportionated CDW by covalent bond- ing Ir dimers was also presented [8]. However, though the origin of the superstructure formation becomes more and more clear, the underlying mechanism of the appearance of superconductivity by doping Pd or Pt is still obscure.
