# Uncovering the Atomic Structure of Substitutional Platinum Dopants in MoS2 with Single-Sideband Ptychography

## TL;DR

This study uses a new imaging technique to precisely identify how platinum atoms are placed in a 2D material, improving understanding of atomic-scale structures.

## Contribution

The paper introduces single-sideband ptychography as a superior method for identifying defect and dopant structures in 2D materials.

## Key findings

- SSB imaging reliably distinguishes defect types like sulfur vacancies with better contrast than HAADF STEM.
- Pt dopant structures in MoS2 are identified at lower electron doses, reducing beam-induced damage.
- SSB offers a pathway for detailed structural analysis of 2D materials at the atomic scale.

## Abstract

We substitute individual Pt atoms into monolayer MoS2 and study the resulting atomic structures with single-sideband
ptychography
(SSB) supported by ab initio simulations. We demonstrate
that while high-angle annular dark-field (HAADF) scanning transmission
electron microscopy (STEM) imaging provides excellent Z-contrast, distinguishing some defect types such as single and double
sulfur vacancies remains challenging due to their low relative contrast
difference. However, SSB with its nearly linear Z-contrast and high phase sensitivity enables reliable identification
of these defect configurations, as well as various Pt dopant structures
at significantly lower electron doses. Our findings uncover the precise
atomic placement and highlight the potential of SSB for detailed structural
analysis of dopant-modified 2D materials while minimizing beam-induced
damage, offering new pathways for understanding and engineering atomic-scale
features in 2D systems.