An electrically switchable anti-ferroelectric bilayer In2Se3 based opto-spintronic device.

Based on non-equilibrium Green's function combined with density functional theory (NEGF-DFT), we theoretically investigate the spin-related photogalvanic effect (PGE) in two anti-ferroelectric bilayer In2Se3 structures by atomic first-principles calculations. It is found that, due to the absence of inversion symmetry and the presence of strong spin-orbital interaction (SOI) in anti-ferroelectric bilayer In2Se3, the photoinduced charge-to-spin conversion can be achieved via the PGE. The generated spin-dependent photocurrent is largely spin-polarized and the corresponding spin polarization can vary from 0% to 100% depending on the photon energies, polarization and incident angles. Furthermore, it is found that, by tuning the polarization and the incident angles of light, the fully spin-polarized and pure spin photocurrent can be obtained. Most importantly, the spin dependent photocurrent can be largely tuned through the transition between two anti-ferroelectric bilayer In2Se3 states by the gate voltage. The defined relative spin dependent photoresponse change ratio ns between two states is extremely large and its maximum value can be in the order of ∼104. Therefore, our work demonstrates the great potential of bilayer In2Se3's novel application in two-dimensional non-volatile opto-spintronic devices.