Mn3Sn is a material that has attracted a lot of attention lately for its topologically non-trivial band structure, which leads to very promising spintronic properties. In this work we experimentally demonstrate that an epitaxially grown thin film of Mn3Sn acts as a source of THz radiation at room temperature when irradiated by a femtosecond laser pulse. By combining various experimental measurements as a function of pump polarisation, magnetic field, and sample orientation we are able to explain the origin of the THz emission with the photocurrents generated via the photon drag effect. A thorough symmetry analysis combined with electronic band structure calculations using density-functional theory (DFT) are used to support our conclusions and provide a guide towards the important features that lead to photocurrent generation, which is useful for designing ultra-fast current pulses emitters.
Here, the authors show that when non-collinear antiferromagnet Mn3Sn is pumped by femtosecond laser pulses it acts as a source of picosecond current pulses that emit electro-dipole radiation in the THz range of the spectrum. The origin of these photo-currents are attributed to the photon drag effect.