Floquet Engineering of Black Phosphorus upon Below-Gap Pumping

Area of Science:

• Condensed Matter Physics
• Quantum Materials Science
• Photonics

Background:

• Time-periodic light fields can modify electronic states in quantum materials, inducing novel properties.
• Floquet engineering, particularly with below-band-gap light, is promising but lacks direct experimental validation of momentum-resolved band renormalization.

Purpose of the Study:

• To provide direct experimental evidence of light-induced band renormalization in black phosphorus.
• To investigate the effects of below-band-gap pumping on electronic band structure.
• To differentiate between below-gap and near-resonance pumping effects.

Main Methods:

• Experimental investigation using black phosphorus as a quantum material.
• Application of time-periodic light fields with photon energy of 160 meV (below the band gap).
• Momentum-resolved band structure analysis to observe renormalization effects.

Main Results:

• Direct experimental evidence of light-induced band renormalization was observed in black phosphorus.
• The distinct effects of below-band-gap pumping versus near-resonance pumping were experimentally revealed.
• Demonstration of light-induced band engineering via below-band-gap excitation.

Conclusions:

• Below-band-gap pumping effectively induces band renormalization in quantum materials like black phosphorus.
• This work validates and extends the principles of Floquet engineering.
• Findings offer crucial insights for applying Floquet engineering to a broader range of quantum materials.