Band-Edge Mixture Engineered Giant and Switchable Shift Current Generation

Area of Science:

• Materials Science
• Condensed Matter Physics
• Optoelectronics

Background:

• Two-dimensional (2D) materials offer significant potential for bulk photovoltaic effect (BPVE) applications.
• Enhancing and controlling BPVE is crucial for advancing optoelectronic devices.

Purpose of the Study:

• To investigate mechanisms for enhancing shift current generation in 2D materials.
• To demonstrate a controllable and switchable BPVE in a realistic material system.

Main Methods:

• Utilized a simplified Hamiltonian model to explore band mixing effects on optical absorption and shift current.
• Employed density functional theory (DFT) calculations and a tight-binding model for the C3B/C3N bilayer.
• Analyzed interfacial interactions and electron transfer between layers.

Main Results:

• Demonstrated that substantial band mixing significantly enhances shift current generation.
• Achieved a giant in-plane shift current exceeding ~1500 μA/V² in the C3B/C3N bilayer due to interfacial electron transfer.
• Showed that interlayer sliding can reverse the direction of the in-plane shift current.

Conclusions:

• A feasible approach for achieving giant and switchable nonlinear optical processes in 2D materials has been proposed.
• The findings highlight the potential of engineered 2D heterostructures for advanced photovoltaic and nonlinear optical applications.