Modeling Spin-Orbitronics Effects at Interfaces and Chiral Molecules

Using orbital angular momentum (OAM) currents represents a growing field in nanoelectronics known as "spin-orbitronics". Here, using the electronic wave packets approach, we explore the possibility of generation and propagation of orbital currents in two representative systems: an oxidized copper surface (where large OAMs are formed at the Cu/O interface) and a model carbon chain/chiral molecule junction. In the Cu/O system, the orbital polarization of incident wave packets is strongly enhanced at the Cu/O interface but rapidly decays in bulk copper. Interestingly, if a finite transmission across the oxygen layer is allowed (a tunnel junction), a significant spin-polarization of transmitted current is predicted; it persists at long distance and can be tuned by applied in-plane voltage. For molecular junctions, the mixing of carbon p_x, p_y channels by a chiral molecular orbital gives rise to efficient generation of orbital current and to its long-range propagation along the carbon chain.