Strain-induced large spin splitting and persistent spin helix at LaAlO3/SrTiO3 interface

We investigate the effect of tensile strain on spin splitting at the n-type interface of LaAlO3/SrTiO3 in terms of spin–orbit coupling coefficient α and spin texture in the momentum space using first-principles density-functional calculations. Our results show that α could be controlled by the tensile strain, and can be enhanced by up to 5 times for a tensile strain of 7%, and the effect of the tensile strain leads to a persistent spin helix, which has a long spin lifetime. The strain effect on the LaAlO3/SrTiO3 interface is important for various applications such as spin field-effect transistors and spin-to-charge conversion.