Investigating the Stable Structures and Topological Insulator Characteristics of Honeycomb AuTe Monolayer Through Decorating with Alkali Metal Atoms, as well as the Effects of Strain and Layering: a First-Principle Study

Abstract

In this study, first-principles calculations are used to systematically study the structural, mechanical, and optical properties of the honeycomb AuTe monolayer, as well as the influence of layered structures on their stability and electronic properties. Additionally, the effect of alkali metal atoms decorating AuTe-X (X = Li, Na, K) and related structural, electronic, optical, and topological insulator properties, along with the biaxial strain on the lithium-decorated AuTe-Li monolayer are investigated. The AuTe monolayer shows metallic characteristics, and when alkali metal atoms are decorated onto it, the resulting structures remain dynamically stable. Notably, the introduction of Li, Na, and K atoms induces bandgap opening in the decorated Li and Na monolayers near the Fermi level, causing metal-to-narrow bandgap semiconductor and Dirac semi-metal transitions. Conversely, the metallic nature of the decorated AuTe-K monolayer is retained. The emergence of a bandgap near the Fermi level, caused by alkali metal decoration, triggers a topological phase transition in AuTe-Li, AuTe-Na, and AuTe-K monolayers. Optical analyses reveal that AuTe-K decorated structure enhances light absorption in the visible spectrum. Consequently, the findings provide insights into the decoration of these two-dimensional material monolayers, potentially advancing research and motivating the production of such monolayers for current nanodevice applications. © 2024 Wiley-VCH GmbH.