Acoustic generation of orbital currents.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• The crystal field in solids couples electronic orbital degrees of freedom to lattice vibrations.
• Exciting lattice dynamics can potentially trigger orbital angular momentum dynamics, generating orbital currents.
• The interplay between orbital currents and lattice dynamics remains largely unexplored.

Purpose of the Study:

• To demonstrate the generation of orbital currents by lattice dynamics.
• To investigate the acoustoelectric properties of Ti/Ni bilayers under surface acoustic waves (SAWs).
• To explore acoustic orbital pumping via acoustically driven ferromagnetic resonance.

Main Methods:

• Utilizing surface acoustic waves (SAWs) to excite lattice dynamics in Ti/Ni bilayers.
• Measuring acoustoelectric properties to detect generated orbital currents.
• Employing acoustically driven ferromagnetic resonance to study acoustic orbital pumping.

Main Results:

• Observed the acoustic orbital Hall effect, generating orbital currents transverse to SAW propagation.
• Demonstrated the generation of orbital currents by lattice dynamics.
• Showcased acoustic orbital pumping in Ti/Ni bilayers.

Conclusions:

• Lattice dynamics can effectively generate orbital currents.
• The acoustic orbital Hall effect is a viable phenomenon.
• Findings pave the way for the development of acoustic orbitronics.