Structural phase transition and electronic structure evolution in Ir1-xPtxTe2 studied by scanning tunneling microscopy

摘要

The IrTe2 transition metal dichalcogenide undergoes a series of structuraland electronic phase transitions when doped with Pt. The nature of each phaseand the mechanism of the phase transitions have attracted much attention. Inthis paper, we report scanning tunneling microscopy and spectroscopy studies ofPt doped IrTe2 with varied Pt contents. In pure IrTe2, we find that the groundstate has a 1/6 superstructure, and the electronic structure is inconsistentwith Fermi surface nesting induced charge density wave order. Upon Pt doping,the crystal structure changes to a 1/5 superstructure and then to aquasi-periodic hexagonal phase. First principles calculations show that thesuperstructures and electronic structures are determined by the global chemicalstrain and local impurity states that can be tuned systematically by Pt doping.