While classical spintronics relies on the use of ferromagnetic materials to generate and detect spin currents, spin-orbitronics exploits the spin-orbit coupling (SOC) in non-magnetic systems to reach this goal. An efficient spin current detection and generation has been achieved in heavy metals such as Pt, W or Ta thanks spin to charge interconversion due to the Spin Hall Effect. However, an even larger interconversion was made possible by the use of the Direct and Inverse Edelstein Effect (EE and IEE) in systems with broken inversion symmetry at interfaces, inducing Rashba SOC.
We observed the IEE in an in interfaces-engineered high-carrier-density SrTiO3 two-dimensional electron gas (2DEG) by mean of SP-FMR. This interconversion can be modulated by the application of a gate voltage, reaching very high values thanks to the enhanced Rashba splitting due to orbital mixing, and the vicinity of the 2DEG Fermi level with an of avoided band crossing with topologically non-trivial order [1].
By combining this high interconversion efficiency with induced ferroelectric properties in SrTiO3, we show that it is possible to control the sign of the spin to charge interconversion in a non-volatile fashion by manipulating the spin orbit properties of the 2DEG through an electric control of the polarization direction [2].
This electrically controlled non-volatile interconversion sign switching opens the way to ultra-low power spintronics, in which non-volatility would be provided by ferroelectricity rather than by ferromagnetism.
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