Engineering Transistorlike Optical Gain in Two-Dimensional Materials with Berry Curvature Dipoles.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Optoelectronics

Background:

• Conventional transistors are point-type devices crucial for electronic circuits.
• Implementing a distributed transistor-like optical response in bulk materials presents an interesting challenge.
• Two-dimensional (2D) metallic systems with low symmetry are proposed as potential candidates for this functionality.

Purpose of the Study:

• To investigate the feasibility of achieving a distributed transistor-type optical response in low-symmetry 2D metallic systems.
• To characterize the optical conductivity of a 2D material under static electric bias using the semiclassical Boltzmann equation.
• To uncover and analyze novel electro-optic (EO) effects that could lead to optical gain and transistor-like behavior.

Main Methods:

• Utilized the semiclassical Boltzmann equation approach to model optical conductivity.
• Analyzed the linear electro-optic (EO) response, linking it to Berry curvature dipole and nonreciprocal optical interactions.
• Investigated a specific material realization using strained bilayer graphene.

Main Results:

• Identified a novel non-Hermitian linear EO effect in biased 2D materials.
• Demonstrated that this effect can induce optical gain and a distributed transistor response.
• Showcased significant optical gain in strained bilayer graphene, dependent on light polarization and multilayer configuration.

Conclusions:

• Low-symmetry 2D metallic systems offer a promising platform for realizing distributed transistor-type optical responses.
• The novel non-Hermitian linear EO effect provides a mechanism for optical gain and transistor functionality.
• Strained bilayer graphene presents a viable material system for exploiting these effects in optical devices.