Coherent spin-wave transport in an antiferromagnet

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Information Science

Background:

• Magnonics utilizes spin waves (magnons) as information carriers for lower dissipation compared to spintronics.
• Antiferromagnets offer terahertz (THz) frequencies for high-speed, low-dissipation information transfer.
• Generating short-wavelength coherent magnons in antiferromagnets has been a significant challenge.

Purpose of the Study:

• To develop a method for efficient emission and detection of short-wavelength coherent magnons in antiferromagnets.
• To explore the potential of antiferromagnetic materials for ultrafast magnonic logic circuits.
• To investigate the use of ultrashort laser pulses for generating and controlling THz spin waves.

Main Methods:

• Utilized ultrashort laser pulses to excite antiferromagnetic DyFeO3.
• Leveraged subwavelength laser field confinement due to high absorption to create non-uniform spin excitation.
• Employed optical methods for efficient emission and detection of propagating magnons.

Main Results:

• Successfully generated and detected a nanometer-scale wavepacket of coherent propagating magnons.
• Observed magnons with a shortest wavelength of 125 nm.
• Measured supersonic propagation velocities exceeding 13 km/s.

Conclusions:

• Demonstrated efficient generation of coherent, short-wavelength THz spin waves in an antiferromagnet.
• This work provides a new source of coherent short-wavelength spin carriers.
• Opens new avenues for THz antiferromagnetic magnonics and coherence-mediated logic devices.