Shulou(Shulou.com)11/24 Report--

Thanks to CTOnews.com net friend Xiao Zhan cut cut, grass Luo Yuzi clue delivery! CTOnews.com March 12 news, CTOnews.com learned from the official website of Shanghai University of Science and Technology, recently, Shanghai University of Science and Technology School of Material Science and Technology Professor Lu Wei research group in photon-magneton interaction and strong coupling regulation direction has made important progress. For the first time, the research team discovered a new magnetic resonance in ferromagnetic insulator single crystals, named photoinduced magneton states, which opened up a whole new dimension for the study of magneton electronics and quantum magnetism. The new strong coupling state of magneton revealed in the study can greatly change the electromagnetic properties of ferromagnetic single crystal and provide a new idea for the entanglement of photons and magnetons, which plays an important role in promoting the application of magnetons in microwave engineering and quantum information processing. The results were published in the flagship journal Physical Review Letters.

Chip development follows Moore's Law, which states that chip performance doubles every 18 months to two years. However, with the gradual entry of human society into the post-Moore era, blindly reducing the chip process has been "challenged to the limit." The time for processor performance to double has been extended, and the momentum of "surge" has encountered technical bottlenecks. Driven by market demand, people urgently need the injection of "fresh blood" to activate the way out of low power consumption, high integration and high information density information processing carriers. The rapid development of spinelectronics and magnetronics based on the development of magnetic materials provides a way to break through the above limitations.

The origin of macroscopic magnetism is mainly unpaired electrons in materials. Electrons have two well-known fundamental properties: charge and spin. The former is the object of all electronic manipulation. The development of microelectronic devices using the properties of electronic charge has triggered a revolution in the information industry. However, facing the ohmic loss that is difficult to suppress, and the desire of the information industry for higher density storage and advanced quantum computing, people urgently hope to further use electron spin as an information carrier to develop spintronic devices, and then continue to promote the development of information technology. Especially the spin in magnetic insulator, they can avoid ohmic loss of conduction electrons completely, and give full play to the advantages of long life and low dissipation of spin, so it is of great significance to develop spintronic devices. Magneton state is a core concept in electron spin applications, which is collective spin excitation in magnetic materials. It can not only transfer the spin current efficiently, but also interact with different physical systems, such as phonons, photons, electrons, etc., and then reshape the acousto-optic and electromagnetic properties of materials. In addition, magnetons can interact with superconducting qubits and play an important role in quantum information technology. Because of these properties and application potential, the research on magneton has attracted great attention in international academic circles in recent years, and new fields such as magneton electronics and quantum magnetoelectronics have been born successively.

Magneton states in ferromagnetic insulator single crystal spheres were first described by American physicist Robert L. White and Irvin H. Slot Jr. discovered in experiments. According to their experimental results, L. R. Walker gives a mathematical description of the spatially confined magneton states of magnetic blocks, called Walker modes. In the following 70 years, almost all the magneton states studied in bulk magnetic materials belong to the category of Walker modes. The discovery of Professor Lu Wei's team broke through this category and discovered new magneton states. Under low magnetic field, when a ferromagnetic insulator single crystal sphere is excited by strong microwave, the unsaturated spins in the interior will obtain some synergy, generating a spin wave oscillating at the same frequency as the microwave excitation signal (Figure (a)), which can be called "pump-induced magnon mode (PIM)." The light-induced magneton state acts as a "dark" state that cannot be observed directly by conventional detection methods, but can be observed indirectly through energy level splitting due to its strong coupling with Walker modes (Figure (b)). The effective spin number of the photoinduced magneton state is regulated by the excitation microwave, so when the power of the excitation microwave is changed, the size of the coupling splitting varies according to the power quarter (Figure (c)), showing a different power dependence from that of the conventional Autler-Townes splitting. In addition, the research team also found that the light-induced magneton states have rich nonlinearities that produce a magneton frequency comb (Figure (d)). Compared with frequency combs generated in microwave resonant circuits, the new frequency combs generated in this insulator do not have electronic noise, so it is expected to achieve ultra-low noise signal conversion in information technology.

Fig.(a) Principle diagram of optically induced magneton states,(b) Strong coupling dispersion diagram of optically induced magneton states,(c) Power dependence of strong coupling splitting on microwave excitation power,(d) Pure magneton frequency comb induced by nonlinear effect of optically induced magneton. We can get rid of this dependence and produce strong coupling states of magnetons by microwave induction. Such coupled states with open boundaries are expected to combine orderly like Lego and obtain rich functionality. Professor Lu Wei, head of the team, said,"The frequency comb is like a vernier caliper, which can accurately measure the disturbance on the spectrum. Using this principle, optical frequency combs have demonstrated amazing accuracy in atomic clocks and ultra-sensitive detection. The frequency combs we found are in the microwave band, which is the frequency band used by radar, communications, and wireless transmission of information, and we can predict that our frequency combs will certainly play a role in these fields. "

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