Strain-controlled high harmonic generation with Dirac fermions in silicene

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanoscience

Background:

• Two-dimensional (2D) materials with zero band gaps possess tunable electronic properties.
• High harmonic generation (HHG) in these materials is crucial for nanoscale optoelectronics and studying massless Dirac fermions.
• Controlling HHG by modulating material electronic structures remains an underexplored area.

Purpose of the Study:

• To investigate the control of HHG in 2D materials through mechanical strain.
• To explore the impact of mechanical engineering on the electronic structures of 2D materials.
• To demonstrate a method for enhancing HHG intensity via strain engineering.

Main Methods:

• Utilizing an ab initio approach based on time-dependent density-functional theory (TDDFT).
• Applying biaxial and uniaxial mechanical strains to monolayer silicene.
• Analyzing the modulation of band structures and preservation of Dirac cones.

Main Results:

• HHG process is sensitive to strain-induced band structure modulations in silicene.
• Significant enhancement of harmonic intensity, up to an order of magnitude, was observed.
• Strain preserved the Dirac cones in the monolayer silicene.

Conclusions:

• Mechanical tuning of electronic structures offers controllable HHG in 2D materials.
• Strain engineering in silicene can significantly enhance HHG intensity.
• This approach opens avenues for efficient solid-state optoelectronic nano-devices and understanding ultrafast nonlinear responses in Dirac materials.