Visualizing the Pt doping effect on surface and electronic structure in Ir_{1-x}Pt_{x}Te_{2} by scanning tunneling microscopy and spectroscopy

TL;DR

This study uses STM and STS to investigate how Pt doping affects the surface and electronic structures of Ir_{1-x}Pt_{x}Te_{2}, revealing structural transitions, supermodulation, and local electronic changes near dopants.

Contribution

It provides detailed microscopic insights into the effects of Pt doping on surface structure and electronic properties in Ir_{1-x}Pt_{x}Te_{2}, advancing understanding of its phase behavior.

Findings

Supermodulation with fixed wave vector in structural transition compounds

Patch structures observed in superconducting samples

Local density of states changes near dopant sites

Abstract

We report on the Pt doping effect on surface and electronic structure in Ir$_{\mathrm{1-x}}$Pt$_{\mathrm{x}}$Te$_ {\mathrm{2}}$ by scanning tunneling microscopy (STM) and spectroscopy (STS). The surface prepared by cleavage at 4.2 K shows a triangular lattice of topmost Te atoms. The compounds that undergo structural transition have supermodulation with a fixed wave vector $q = \frac{2\pi}{5a_m}$ (where $a_m$ is the lattice constant in the monoclinic phase) despite the different Pt concentrations. The superconducting compounds show patch structures. The surface of the compound that exhibits neither the superconductivity nor the structural transition shows no superstructure. In all doped samples, the dopant is observed as a dark spot in STM images. The tunneling spectra near the dopant show the change in the local density of state at approximately -200 mV. Such microscopic effects of the dopant give us the keys for establishing a microscopic model of this material.