Rectification of acoustic phonons in harmonic chains with nonreciprocal spring defects

Area of Science:

• Condensed matter physics
• Acoustics
• Phononics

Background:

• Investigating acoustic phonon scattering is crucial for understanding energy transport in materials.
• Nonreciprocal systems offer unique transport properties not found in reciprocal systems.

Purpose of the Study:

• To investigate acoustic phonon scattering by nonreciprocal spring defects in a harmonic chain.
• To explore the resulting rectification effects and energy exchange mechanisms.

Main Methods:

• Simulating acoustic phonon scattering in a harmonic chain model.
• Introducing nonreciprocal spring defects parameterized by Δ.
• Analyzing transmission, reflection, and energy exchange.

Main Results:

• Demonstrated a pronounced rectification effect with directional transmission of acoustic phonons.
• Showcased energy exchange between the system and the medium due to nonreciprocity.
• Observed cooperative actions between defects mediated by resonant cavity modes.
• Found that damping forces enhance the rectification of reflected vibrational waves.

Conclusions:

• Nonreciprocal defects in harmonic chains can induce significant directional control over acoustic phonon transport.
• The interplay between nonreciprocity, defects, and damping offers potential for novel phononic devices.
• Cooperative effects between defects highlight complex emergent behaviors in driven systems.