Graphene-like monolayer monoxides and monochlorides.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Computational Chemistry

Background:

• Two-dimensional (2D) monolayer materials, with atomic-level thickness, are derived from layered structures.
• The discovery of new graphene-like 2D materials has slowed, with existing catalogs considered nearly complete.

Purpose of the Study:

• To explore and report novel 2D graphene-like monolayers beyond conventional material classes.
• To investigate the potential of using first-principle calculations to predict new 2D materials.
• To assess the stability and synthesis strategies for these newly discovered 2D materials.

Main Methods:

• Utilized first-principle calculations to predict the formation of 2D graphene-like monolayers.
• Investigated monoxides (e.g., BeO, MgO) and rock-salt structured monochlorides (e.g., LiCl, NaCl).
• Explored 2D materials with d-orbital atoms (e.g., HfO, CdO, AgCl) and predicted mononitrides (ScN) and monoselenides (CdSe).
• Employed stress engineering to analyze and enhance the stability of the 2D monolayers by examining phonon dispersion relations.

Main Results:

• Successfully identified and reported 2D graphene-like monolayers from various oxides and monochlorides.
• Predicted the existence of 2D materials containing d-orbital atoms, mononitrides, and monoselenides.
• Demonstrated that stress engineering effectively stabilizes 2D monolayers by eliminating imaginary phonon frequencies.
• Confirmed high dynamic, thermal, kinetic, and mechanical stability in the synthesized 2D materials, attributed to atomic hybridization and electronic delocalization.

Conclusions:

• This study expands the known catalog of 2D graphene-like materials significantly.
• First-principle calculations combined with stress engineering offer a viable strategy for discovering and stabilizing novel 2D materials.
• The newly discovered 2D monolayers possess robust stability, making them promising candidates for future applications.