Ultrafast spin-charge interconversion in Rashba states probed by time-domain THz spectroscopy

THz emission spectroscopy reveals to be a very powerful experimental method to investigate the properties of Rashba or topological insulator surface states. The THz emission can be also used in heavy metallic or in more general Rashba systems. We prove here the ability of the present method. In 3d/5d transient metal bilayers and beyond heavy metal structures, Rashba states and Topological insulators are expected candidates for spintronic-terahertz domains due to their high spin to charge conversion properties. In this scheme, we are interested in the samples based on 2D electron gas, topological insulators and Heusler alloys with strong spin-orbit coupling.