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

TL;DR

This study investigates how Pt doping influences the structural and electronic phase transitions in IrTe2 using scanning tunneling microscopy and spectroscopy, revealing changes in superstructures and electronic states.

Contribution

It provides detailed STM/STS analysis of phase evolution in Pt-doped IrTe2 and links structural changes to chemical strain and impurity effects.

Findings

Pure IrTe2 has a 1/6 superstructure with non-nesting electronic structure.

Pt doping induces a transition to a 1/5 superstructure and a hexagonal phase.

Superstructures are governed by chemical strain and impurity states, tunable by doping.

Abstract

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