Spintronics refers to the study of the role that electron spin plays in solid state physics and the possible devices that specifically exploit spin properties instead of, or in addition to, charge degrees of freedom. For practical applications, novel materials with long spin lifetimes and allowable spin coherent manipulation are paramount. In this colloquium, I will present (i) a novel way of manipulating electron spins in organic semiconductors (OSECs) by magnetic nanoparticles (MNPs)[1], and (ii) the role of Rashba spin-orbit coupling (SOC) in the optoelectronic and spin response in 2D and 3D organic/inorganic hybrid lead halide perovskite materials [2]. For the former, we demonstrated that Fe3O4 MNPs with superparamagnetic properties generate large magnetic dipole–dipole interaction with electron spins in OSECs. This interaction was found to be analogous to the effects of hyperfine interaction. Our study yields a new pathway for tuning OSECs’ magnetic functionality, which is essential for organic optoelectronic devices and magnetic sensor applications. For the latter, the presence of heavy Pb atoms in the perovskite crystal leads to a large intrinsic SOC, which, when combined with the breaking of the inversion symmetry, gives rise to giant Rashba-type SOC. In this part, I will show our preliminary results of Rashba SOC strength from 2D and 3D perovskites that depends on their structural inversion symmetry breaking, using several spintronic tools including magnetic field effects on conductivity, magnetic circular dichroism, and circular photoluminescence spectroscopy. Materials with strong Rashba SOC are particularly useful for electric-field controlled spin dynamics for future spin transistor logic devices.

[1] Geng et al. DOI: 10.1039/c9mh00265k (2019)
[2] Stranks et at. Nature Materials17, 381–382 (2018)