Ultrafast helicity-dependent photocurrents in Weyl Magnet Mn3Sn
jats:titleAbstract</jats:title>jats:pMnjats:sub3</jats:sub>Sn 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 Mnjats:sub3</jats:sub>Sn 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.</jats:p>
Acknowledgements: C.C. and D.H. acknowledge support from the Royal Society. G.F.L. is funded by the Aker Scholarship. R.J.S. acknowledges funding from a New Investigator Award, EPSRC grant EP/W00187X/1, as well as Trinity college, Cambridge. G.F.L. thanks B. Peng, S. Chen, U. Haeusler and M.A.S. Martínez for useful discussions.