Wednesday 12th April 2023 at 3pm, Yong Xu (Hefei Innovation Research Institute, Beihang University, Hefei 230013, China) will give a seminar on Emission Mechanisms in Spintronic Terahertz Emitters in the Auditorium.
Abstract : Spintronic thin films were shown to be promising high-performance broadband terahertz (THz) emitters. For conventional spintronic THz emitters, THz emission arises from three mechanisms : the magnetic dipolar radiation due to the ultrafast demagnetization, the transient current radiation due to spin-charge conversion, and anomalous Hall effect. Recent progress in orbitronics reveals the possibility of using orbit current as an information carrier. In this study, we show that ultrafast pulses of orbit current can be generated in Ni layers by femtosecond laser pulses. We demonstrate that, by injecting such orbit current pulses into nonmagnetic metals, a transient charge current is induced and emits terahertz electromagnetic pulses. The nonmagnetic metal layer acts as a converter of the orbit current into the charge current. The discovery of the generation and conversion of light-induced orbit current opens a new route for developing future spintronic THz devices.
