Novel Pd_{2}Se_{3} Two-Dimensional Phase Driven by Interlayer Fusion in Layered PdSe_{2}

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) materials are typically fabricated from layered bulk materials, with their monolayer form mirroring a single bulk layer.
• Palladium diselenide (PdSe2) is a layered material where the monolayer form is theoretically stable but has not been experimentally fabricated.
• This discrepancy presents a challenge in 2D material synthesis.

Purpose of the Study:

• To investigate the fabrication of monolayer palladium diselenide (PdSe2).
• To understand the structural and stoichiometric transformations during monolayer formation.
• To explore the role of defects in creating novel 2D materials.

Main Methods:

• Atomic-scale imaging using scanning transmission electron microscopy (STEM).
• First-principles calculations using density functional theory (DFT).
• In-situ defect creation via electron irradiation in layered PdSe2.

Main Results:

• The preferred monolayer form of PdSe2 results from the melding of two bulk monolayers, with selenium atom emission, yielding a Pd2Se3 stoichiometry.
• Interlayer melding is confirmed by creating selenium vacancies in PdSe2 using electron irradiation.
• Defect-induced strong interlayer interactions can lead to the formation of new 2D materials.

Conclusions:

• The experimental fabrication of a novel 2D material, Pd2Se3, from PdSe2 is achieved through a defect-mediated interlayer melding process.
• This discovery highlights the potential of defect engineering to create new 2D structures.
• Opens new avenues for exploring novel 2D materials and their synthesis.