This study, published in the journal Nature, demonstrates the possibility of modulating magnetic information using electrical pulses while converting them into a circularly polarized light signal in light-emitting diodes (SpinLEDs), at room temperature and zero applied magnetic field. The underlying physical principle is based on transfers between the angular momentum of electrons and photons. Thanks to spin-orbit coupling, a control charge current generates a spin current through the spin Hall effect, electrically reversing the magnetization of the ferromagnetic part. This switching then determines the spin orientation of the carriers injected into the semiconductors, in which the transfer of angular momentum from the electron spin to the photon controls the circular polarization of the emitted light.  This breakthrough lies at the interface between spintronics and photonics. The results obtained with these on-demand sources of polarized photons point the way to developments in several fields: chirality analysis of molecules, spin-controlled single-photon sources for quantum technologies, 3D displays, etc. In particular, these devices offer interesting potential in the field of free-space optical communications, since electrically-controlled modulation of the circular polarization of the emitted light, rather than its intensity, could be achieved on ultra-fast timescales, with low energy consumption. The information carried by the helicity (i.e., the direction of rotation of the electrical component of the light) of the photons emitted by spinLEDs propagates over distances of several tens of centimeters, in contrast to current spintronic systems, where the information carried by the spin propagates over nanometric or micrometric distances. This could be exploited in ultra-fast, high-performance optical transmitters for data centers, Light-Fidelity (LiFi) applications or neuromorphic computing for artificial intelligence. In addition, semiconductor laser diodes, known as “spin-lasers”, can also be envisaged, with higher data rates than today’s laser diodes, paving the way for fast, long-distance communications. Finally, we can also imagine further reducing the size of these devices to ultimate scales by using two-dimensional materials.

Reference:

P. A. Dainone, N. Figueiredo Prestes, P. Renucci, A. Bouché, M. Morassi, X. Deveaux, M. Lindemann, J-M. George, H. Jaffrès, A. Lemaître, B. Xu, M. Stoffel, T. Chen, L. Lombez, D. Lagarde, G. Cong, T. Ma, P. Pigeat, M. Vergnat, H. Rinnert, X. Marie, X. Han, S. Mangin, J-C Rojas-Sanchez, J-P Wang, M.C Beard, N.C Gerhardt, I. Zutic and     Y. Lu

 

Controlling the helicity of light by electrical magnetization switching

Nature 627, 783-788 (2024) published online March 27, 2024

 

https://rdcu.be/dCFs3

https://doi.org/10.1038/s41586-024-07125-5

 

See also News and Views “Electrons flip a switch on optical communications” S. Hiura, Nature 627, 737 (2024)

 

Contacts:

 

Pierre Renucci, Professor at Institut National de Sciences Appliquées de Toulouse (INSAT), Laboratoire de Physique et Chimie des Nano-Objets (LPCNO), INSA-CNRS-UPS, Université de Toulouse

Email: renucci@insa-toulouse.fr

 

Yuan Lu, CNRS Researcher at Institut Jean Lamour (CNRS/Université de Lorraine)

Email: yuan.lu@univ-lorraine.fr