Speaker: Dr. Dali Sun, NC State Dept of Physics

Dali Sun

Speaker: Dr. Dali Sun, Assistant Professor, North Carolina State University Department of Physics

Title: Spintronic Terahertz Emission from Two-Dimensional Hybrid Metal Halides

Abstract: Terahertz (THz) technologies hold great promise for the development of future computing and communication systems. The ideal, energy-efficient, and miniaturized future THz devices should consist of lightweight, low-cost, and robust components with synergistic capabilities. However, a paucity of materials systems possessing both these desirable attributes and functionalities has made device realization difficult. Two-Dimensional Hybrid Metal Halides (2D-HMHs) have been shown to allow for facile and economical, solution-based synthesis while still maintaining high energy conversion efficiency, chemical flexibility, and defect tolerance. These attributes make them ideal candidates for high-performance THz communication applications. Spintronic toolkits, on the other hand, can serve as an effective ‘control knob’ for future THz devices when interfacing HMHs with ferromagnetic (FM) materials, taking advantage of the fast relaxation of spin (akin to a ‘switch’) and the couplings between magnons, photons, and spins. The broken inversion symmetry and resulting giant Rashba state formed at the 2D-HMH surface allow for the spintronic control of intensive THz generation. In this talk, we will present the observation of spintronic-THz radiation in 2D-HMHs interfaced with a ferromagnetic metal, produced by the ultrafast spin current under femtosecond laser excitation. Our work demonstrates the capability for the coherent control of THz emission from 2D-HMHs, enabling their promising applications on the ultrafast timescale as solution-processed material candidates for future THz emitters.

Biography: Dr. Sun’s research interests are in spintronics and optoelectronics of organic semiconductors, magnetic thin films, and organic-inorganic hybrid perovskites. It includes the studies of organic spin valves, organic light-emitting diodes, hybrid perovskite optoelectronic/spintronics devices, and their device physics. Sun Research Group at NC State focuses on exploring novel routes for spin injection and detection, magnetic field effect, spin Hall effect, and their applications in molecules, polymers, and newly emerged materials. Dr. Sun is one of the pioneers who launched spintronic studies in hybrid perovskite materials.