Ultrafast Spin-Charge Conversion in Rashba states probed by Terahertz time-domain emission spectroscopy

Terahertz (THz) emission spectroscopy in spin systems has become a very powerful method to generate THz radiation and to investigate the properties of Rashba or Topological Insulator surface states. Broadband THz emission can be generated in heavy metallic or in more general Rashba systems. In 3d/5d transient metal bilayers THz emission is via the Inverse Spin Hall effect. Beyond heavy metal structures, Rashba states are strong candidates for THz-spintronics owing to their high spin to charge conversion properties. Here we present a 2D Electron Gas with strong Rashba spin-orbit coupling, NiFe/LaAlO 3 /SrTiO 3 , and demonstrate THz emission is via the Inverse Edelstein Effect.