Spin Hall Effect Driven Non-Local Spin Diffusion at Oxide Heterointerfaces

Abstract

The conductive interface at LaAlO3/SrTiO3 (LAO/STO) can be designed to exhibit high mobility with tunable carrier concentration and exhibits various unique electronic behaviors. This interface could be also interesting playground for `'spin-orbitronics'' as the structure itself strongly couple the spin and orbital degree of freedom through the Rashba spin-orbit interaction. We report the non-local spin diffusion at LAO/STO interface induced by the spin Hall effect. The Hall-bar (H-bar) like geometry was employed to generate a transverse spin polarized current, which in turn can be detected by the inverse spin Hall effect. Our results clearly demonstrated the non-local spin diffusion as well as effective spin charge conversion at this oxide heterointerface. The analysis on the non-local spin voltage displays that both D''yakonov-Perel'' and Elliott-Yafet mechanisms involve in the spin relaxation. Our results show that the oxide heterointerface is highly efficient in spin-charge conversion with exceptionally strong spin Hall coefficient γ \textasciitilde 0.24 and could be an outstanding platform for the study of coupled charge and spin transport phenomena and their electronic applications.