Two-Dimensional Noble Metal Chalcogenides in the Frustrated Snub-Square Lattice

Area of Science:

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

Background:

• Two-dimensional (2D) materials offer unique electronic and physical properties.
• Noble metal chalcogenides are a class of materials with potential applications in electronics.
• Geometric frustration in crystal lattices can lead to novel phenomena.

Purpose of the Study:

• To investigate the structural, electronic, and thermodynamic properties of 2D noble metal chalcogenides.
• To explore materials crystallizing in a geometrically frustrated snub-square lattice.
• To assess the potential of these materials for semiconductor applications.

Main Methods:

• First-principles calculations were employed to study the electronic band structures and thermodynamic stability.
• Comparison was made between snub-square and square lattice structures.
• Excitonic effects and binding energies were analyzed.

Main Results:

• Monolayer noble metal chalcogenides ({Cu, Ag, Au}2{S, Se, Te}) were found to be semiconductors with band gaps from 0.1 to over 2.5 eV.
• These materials exhibit near-thermodynamic stability, with Ag2Se being particularly close to the convex hull.
• Strong excitonic effects were observed, with binding energies around 0.3 eV.

Conclusions:

• 2D noble metal chalcogenides in a snub-square lattice are promising semiconductor materials.
• Their near-thermodynamic stability and strong excitonic effects warrant further investigation.
• The Cu(001) surface is proposed as a potential substrate for synthesizing Cu2Se.