Spin-orbit coupling induced ultra-high harmonic generation from magnetic dynamics

Abstract

The recent boost in data transfer rates puts a daring strain on information technology. Sustaining such a growth rate requires the development of sources, detectors and systems working in the so-called TeraHertz (THz) gap covering the frequency window from 0.1 to 10 THz (1 THz = 10${}^{12}$~Hz). This gap represents a challenge for conventional electronic devices due to carrier transit delays ($\sim$1-10ps), as well as for photonic devices due to thermal fluctuations (300K$\sim$6THz). Nonetheless, designing efficient, room-temperature THz sources would constitute a key enabler to applications spanning from high-resolution imaging to extreme wide band wireless communication. Whereas high-harmonic generation in solid is usually limited to less than ten harmonics, broadband THz emission has been demonstrated using laser-induced superdiffusive spin currents in magnetic bilayers composed of a ferromagnet deposited on top of a noble metal. While promising, this technique presents the major disadvantage of necessitating optical pumping and hence lacks scalability. Here, we demonstrate that extremely high harmonic emission can be achieved by exploiting conventional spin pumping, without the need of optical excitation. We show that when the spin-orbit coupling strength is close to the s-d exchange energy, a strongly non linear regime resulting from resonant spin flip scattering occurs leading to the generation of a thousand of harmonics at realistic antiferromagnetic precession frequencies, thereby enhancing both spin and charge dynamics by two orders of magnitude, and allowing for an emission at frequencies above 300 THz.

7 pages, 6 figures

References in corpus (5)

• Super-Diffusive Spin-Transport as a Mechanism of Ultrafast Demagnetization
• Highly efficient and tuneable spin-to-charge conversion through Rashba coupling at oxide interfaces
• Spin pumping and spin-transfer torques in antiferromagnets
• High harmonic generation from Bloch electrons in solids
• What is measured in the scanning gate microscopy of a quantum point contact?

Cited by in corpus (6)

• High-harmonic generation in spin and charge current pumping at ferromagnetic or antiferromagnetic resonance in the presence of spin-orbit coupling
• Pseudo Electric Field and Pumping Valley Current in Graphene Nano-bubbles
• High harmonic generation from electrons moving in topological spin textures
• Controllable single spin evolution at sub-harmonics of electric dipole spin resonance enhanced by four-level Landau-Zener-St{ü}ckelberg-Majorana interference
• Noncollinear antiferromagnetic textures driven high harmonic generation from magnetic dynamics in the absence of spin-orbit coupling
• Resonant second harmonic generation in a two-dimensional electron system