Electronic and structural properties of atomically thin metallenes

TL;DR

This study uses density-functional theory to systematically analyze the electronic and structural properties of 270 atomically thin metal sheets, revealing patterns and providing a comprehensive reference for future experimental and application development.

Contribution

It offers the first extensive catalog of 2D metallic structures with detailed properties, aiding future research and applications in catalysis, sensing, and nanoelectronics.

Findings

Similar properties among simple and noble metals

Bond lengths and cohesion energies follow systematic patterns

Lack of buckled hexagonal lattice in certain metals

Abstract

Although metallic elements favor three-dimensional (3D) geometries due to their isotropic, metallic bonding, experiments have reported metals also with two-dimensional (2D) allotropes, the so-called metallenes. And while bulk metals' electronic and structural properties are well known, the corresponding knowledge for atomically thin metallenes remains scattered. Therefore, in this work, we use density-functional theory to investigate the electronic and structural properties of 45 elemental metals with honeycomb, square, and hexagonal lattices, along with their buckled counterparts, resulting in a comprehensive catalog of 270 metallenes with their properties. We systematically present their structural, energetic, and electronic structure properties and discuss similarities and differences compared to their 3D counterparts. As a result, simple and noble metals exhibit similar characteristics and lack buckled hexagonal lattice. Apart from scattered exceptions, the trends in several properties, such as bond lengths, cohesion energies, and projected densities of states, are governed by coordination numbers and exhibit systematic patterns. This systematic reporting provides a necessary reference for the selection and categorization of metallenes for further experimental efforts to develop them for catalytic, sensing, plasmonic, and nanoelectronics applications.