Spin-orbit coupling induced non-local signal in quasi 2DEG of LAO/STO

Abstract

Oxide hetero interface have received growing attention due to unique electronic behaviors, such as coexistence of superconductivity and ferromagnetism, strong Rashba-type spin-orbit coupling, etc. Here, we studied non-local spin signal of gate-controlled Rashba field in quasi-2DEG of LaAlO3/SrTiO3 (LAO/STO) interface. We fabricated simple hall-bar (H-bar) like geometry to measure non-local signal depends on different channel lengths (2~10um). Cleaned 5mm x 5mm size of LAO/STO sample was patterned using e-beam lithography & Reactive ion etching process. Fabricated sample was putted in a Physical Property Measurement System. And all electrical measurement was performed in a vacuum condition using Keithely source meter (K2636) and nanovoltameter (K2182). When an electric current flows one of the lines of the H-bar structures, a transverse spin current due to the spin orbit coupling is induced in the connecting part. Consequently, this spin current produces a non-local voltage difference in the opposite line of the H-bar structures via inverse spin hall effect. The non-local signals were studied under different angle of magnetic field and variation of applied gate voltage. This work was supported by a grant from (Future Challenge Project or Creativity and Innovation Project) funded by the Ulsan National Institute of Science and Technology and Basic Science Research Program through the National Research Foundation of Korea (No. 2011-0014651