Ab initio engineering of materials with stacked hexagonal tin frameworks

Area of Science:

• Condensed Matter Physics
• Materials Science
• Solid-State Chemistry

Background:

• Atom-thick hexagonal forms of group-IV elements, particularly tin, are predicted to exhibit unique electronic properties.
• Producing sizable two-dimensional (2D) crystallites of tin typically involves deintercalation from bulk compounds with specific tin frameworks.

Purpose of the Study:

• To identify and characterize new synthesizable 2D tin materials.
• To investigate the electronic and topological properties of novel and known tin-based compounds.

Main Methods:

• Ab initio calculations were employed to study the stability and electronic structure of tin compounds.
• Z2 invariants were calculated to predict topological properties.
• The synthesis of NaSn2 under accessible pressures was theoretically assessed.

Main Results:

• A new metal distannide, NaSn2, featuring 3D stacked flat hexagonal layers, was identified as synthesizable under moderate pressures and potentially stable at ambient conditions.
• The known compound BaSn2, with buckled hexagonal layers, was examined.
• Calculated Z2 invariants suggest that NaSn2 may exhibit topologically non-trivial behavior.
• BaSn2 is predicted to be a strong topological insulator.

Conclusions:

• NaSn2 represents a promising new material for exploring topological electronic phenomena, even as an exception to the 8-electron rule.
• BaSn2 is a strong candidate for a topological insulator, contributing to the understanding of topological materials.
• The study highlights the potential of deintercalation methods for discovering novel 2D tin materials with exotic electronic properties.