Probing Broken Time-Reversal Symmetry in 2D Materials with Tailored-Light Photocurrent Generation

Area of Science:

• Condensed Matter Physics
• Quantum Materials
• Spectroscopy

Background:

• The bulk photogalvanic effect generates photocurrents in materials lacking inversion symmetry.
• This effect is useful for electronic applications and probing material properties.
• Studying time-reversal-symmetry (TRS) broken phases requires advanced techniques.

Purpose of the Study:

• To advance bulk photogalvanic photocurrent spectroscopy using tailored laser fields.
• To study TRS-broken phases in 2D systems with ultrafast photocurrent generation.
• To develop a background-free method for probing magnetism and topological phenomena.

Main Methods:

• Utilizing combinations of bichromatic linearly polarized laser beams.
• Investigating photocurrent generation in graphene theoretically and experimentally.
• Employing state-of-the-art ab initio simulations.

Main Results:

• Demonstrated a forbidden photocurrent selection rule in TRS-invariant graphene using tailored light.
• Predicted a broken photocurrent selection rule in intrinsically TRS-broken materials like CrI₃.
• Showcased background-free probing of TRS-broken phenomena.

Conclusions:

• Tailored laser fields can break symmetries and generate photocurrents in 2D systems.
• This method provides a novel way to probe TRS-broken phases, including magnetism.
• The technique does not require external magnetic fields or circularly polarized light.