@misc{SeiboldCapraraGrillietal., author = {Seibold, G{\"o}tz and Caprara, Sergio and Grilli, Marco and Raimondi, Roberto}, title = {Theory of the Spin Galvanic Effect at Oxide Interfaces}, series = {Physical Review Letters}, volume = {119}, journal = {Physical Review Letters}, number = {25}, issn = {1092-0145}, doi = {10.1103/PhysRevLett.119.256801}, abstract = {The spin galvanic effect (SGE) describes the conversion of a nonequilibrium spin polarization into a transverse charge current. Recent experiments have demonstrated a large conversion efficiency for the two-dimensional electron gas formed at the interface between two insulating oxides, LaAlO3 and SrTiO3. Here, we analyze the SGE for oxide interfaces within a three-band model for the Ti t2g orbitals which displays an interesting variety of effective spin-orbit couplings in the individual bands that contribute differently to the spin-charge conversion. Our analytical approach is supplemented by a numerical treatment where we also investigate the influence of disorder and temperature, which turns out to be crucial to providing an appropriate description of the experimental data.}, language = {en} } @misc{SeiboldCapraraGrillietal., author = {Seibold, G{\"o}tz and Caprara, Sergio and Grilli, Marco and Raimondi, Roberto}, title = {Inhomogeneous Rashba spin-orbit coupling and intrinsic spin-Hall effect}, series = {Journal of Magnetism and Magnetic Materials}, volume = {440}, journal = {Journal of Magnetism and Magnetic Materials}, doi = {10.1016/j.jmmm.2016.12.066}, pages = {63 -- 65}, abstract = {The spin-Hall effect is the generation of a transverse spin-current induced by a longitudinal electric field. Among the various scattering mechanisms which can induce a finite spin-Hall effect we focus on the intrinsic contribution arising from a Rashba-type spin-orbit (RSO) coupling which for couplings linear in momentum usually vanishes. Here we show that non-homogeneity in the spin-orbit coupling arising from structure inversion asymmetry gives rise to a finite spin-Hall effect which we exemplify for a system with striped Rashba spin-orbit coupling.}, language = {en} } @misc{SeiboldCapraraGrillietal., author = {Seibold, G{\"o}tz and Caprara, Sergio and Grilli, Marco and Raimondi, Roberto}, title = {Non-equilibrium Spin Currents in Systems with Striped Rashba Spin-Orbit Coupling}, series = {Journal of Superconductivity and Novel Magnetism}, volume = {30}, journal = {Journal of Superconductivity and Novel Magnetism}, number = {1}, issn = {1557-1939}, doi = {10.1007/s10948-016-3774-x}, pages = {123 -- 128}, abstract = {It is shown that non-homogeneity in the spin-orbit coupling (SOC) arising from structure inversion asymmetry gives rise to a finite intrinsic spin Hall conductivity in contrast with the corresponding case of a homogeneous SOC in the disordered two-dimensional electron gas. In particular, we examine the inhomogeneity arising from a striped modulation of the Rashba type spin-orbit coupling. A corresponding structure could be realized at oxide interfaces with periodic top gating or in semiconductor heterostructures.}, language = {en} } @misc{BovenziCapraraGrillietal., author = {Bovenzi, Nicandro and Caprara, Sergio and Grilli, Marco and Raimondi, Roberto and Scopigno, Niccol{\`o} and Seibold, G{\"o}tz}, title = {Density inhomogeneities and Rashba spin-orbit coupling interplay in oxide interfaces}, series = {Journal of Physics and Chemistry of Solids}, journal = {Journal of Physics and Chemistry of Solids}, issn = {0022-3697}, pages = {12}, abstract = {There is steadily increasing evidence that the two-dimensional electron gas (2DEG) formed at the interface of some insulating oxides like LaAlO3/SrTiO3 and LaTiO3/SrTiO3 is strongly inhomogeneous. The inhomogeneous distribution of electron density is accompanied by an inhomogeneous distribution of the (self-consistent) electric field confining the electrons at the interface. In turn this inhomogeneous transverse electric field induces an inhomogeneous Rashba spin-orbit coupling (RSOC). After an introductory summary on two mechanisms possibly giving rise to an electronic phase separation accounting for the above inhomogeneity, we introduce a phenomenological model to describe the density-dependent RSOC and its consequences. Besides being itself a possible source of inhomogeneity or charge-density waves, the density-dependent RSOC gives rise to interesting physical effects like the occurrence of inhomogeneous spin-current distributions and inhomogeneous quantum-Hall states with chiral "edge" states taking place in the bulk of the 2DEG. The inhomogeneous RSOC can also be exploited for spintronic devices since it can be used to produce a disorder-robust spin Hall effect.}, language = {en} } @inproceedings{SeiboldCapraraRaimondi, author = {Seibold, G{\"o}tz and Caprara, Sergio and Raimondi, Roberto}, title = {Theory of charge-spin conversion at oxide interfaces: the inverse spin-galvanic effect}, series = {Spintronics XI, SPIE Nanoscience + Engineering, 19-23 August 2018, San Diego, California, United States}, booktitle = {Spintronics XI, SPIE Nanoscience + Engineering, 19-23 August 2018, San Diego, California, United States}, editor = {Drouhin, Henri-Jean and Wegrowe, Jean-Eric and Razeghi, Manijeh and Jaffr{\`e}s, Henri}, publisher = {Spie}, address = {Bellingham, USA}, doi = {10.1117/12.2319592}, abstract = {We evaluate the non-equilibrium spin polarization induced by an applied electric field for a tight-binding model of electron states at oxides interfaces in LAO/STO heterostructures. By a combination of analytic and numerical approaches we investigate how the spin texture of the electron eigenstates due to the interplay of spin-orbit coupling and inversion asymmetry determines the sign of the induced spin polarization as a function of the chemical potential or band filling, both in the absence and presence of local disorder. With the latter, we find that the induced spin polarization evolves from a non monotonous behavior at zero temperature to a monotonous one at higher temperature. Our results may provide a sound framework for the interpretation of recent experiments.}, language = {en} } @misc{SeiboldCapraraGrillietal., author = {Seibold, G{\"o}tz and Caprara, Sergio and Grilli, Marco and Raimondi, Roberto}, title = {On the Evaluation of the Spin Galvanic Effect in Lattice Models with Rashba Spin-Orbit Coupling}, series = {Condensed matter}, volume = {3}, journal = {Condensed matter}, number = {33}, issn = {2410-3896}, doi = {10.3390/condmat3030022}, pages = {1 -- 10}, abstract = {The spin galvanic effect (SGE) describes the conversion of a non-equilibrium spin polarization into a charge current and has recently attracted renewed interest due to the large conversion efficiency observed in oxide interfaces. An important factor in the SGE theory is disorder which ensures the stationarity of the conversion. Through this paper, we propose a procedure for the evaluation of the SGE on disordered lattices which can also be readily implemented for multiband systems. We demonstrate the performance of the method for a single-band Rashba model and compare our results with those obtained within the self-consistent Born approximation for a continuum model.}, language = {en} } @misc{SeiboldCapraraGrillietal., author = {Seibold, G{\"o}tz and Caprara, Sergio and Grilli, Marco and Raimondi, Roberto}, title = {Intrinsic spin Hall effect in systems with striped spin-orbit coupling}, series = {epl : a letters journal exploring the frontiers of physics}, volume = {112}, journal = {epl : a letters journal exploring the frontiers of physics}, number = {1}, issn = {1286-4854}, doi = {http://dx.doi.org/10.1209/0295-5075/112/17004}, pages = {17004-p1 -- 17004-p6}, language = {en} }