Controlling entangled spin-orbit coupling of 5d states with interfacial heterostructure engineering

The combination of strong electron correlations in 3d transition-metal oxides and spin-orbit interactions in the 5d counterpart can give rise to exotic electronic and magnetic properties. Here, the nature of emerging phenomena at the interface between SrIrO3 (SIO) and La2/3Sr1/3MnO3 (LSMO) is presented. Nominally, SIO with strong spin-orbit interaction is metallic and nonmagnetic on the verge of a metal-insulator transition, whereas LSMO is metallic and ferromagnetic with itinerant character and high spin polarization. In the 1:1 LSMO/SIO superlattice, we observe ferromagnetic Mn moments with an insulating behavior, accompanied by antiferromagnetic ordering in SIO. Element-resolved x-ray magnetic circular dichroism proves that there is a weak net ferromagnetic Ir moment aligned antiparallel to the Mn counterpart. The branching ratio shows the formation of molecular orbitals between the Mn and Ir layers modifying the Ir 5d electronic configuration through the mixture of t2g and eg states, resulting in a deviation from Jeff=1/2. This result demonstrates a pathway to manipulate the spin-orbit entanglement in 5d states with two-dimensional 3d spin-polarized electrons through heterostructure design. © 2018 American Physical Society.