Semiconductor to metal transition in bilayer phosphorene under normal compressive strain

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Phosphorene, a 2D analog of black phosphorus, exhibits high carrier mobilities and a tunable bandgap.
• Current methods for tuning phosphorene's properties, such as high in-plane strains and electric fields, are experimentally challenging.

Purpose of the Study:

• To investigate the electronic property tuning of bilayer phosphorene using normal compressive strain.
• To explore the feasibility of experimentally achievable strain for property modulation.

Main Methods:

• Density functional theory (DFT) based calculations were employed.
• Phonon spectra were analyzed to assess structural integrity under strain.

Main Results:

• A complete and reversible semiconductor-to-metal transition was observed at 7% strain.
• A direct-to-indirect bandgap transition occurred at 4% strain.
• Structural integrity was maintained at higher strain levels, with minimal changes in carrier mobility and effective mass.

Conclusions:

• Normal compressive strain offers a facile and reversible method for tuning the electronic properties of bilayer phosphorene.
• The observed transitions and preserved transport properties facilitate the development of phosphorene-based multi-physics devices.