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The manipulation of the spin degrees of freedom in a solid has been of fundamental and technological interest recently for developing high-speed, low-power computational devices. There has been much work focused on developing highly spin-polarized materials and understanding their behavior when incorporated into so-called spintronic devices.
These devices usually require spin splitting with magnetic fields. However, there is another promising strategy to achieve spin splitting using spatial symmetry breaking without the use of a magnetic field, known as Rashba-type splitting.
Analysis of the magnetotransport reveals anisotropic magnetoresistance, weak anti-localization and quantum oscillation behavior consistent with a large Rashba-type splitting. In the presence of an electric field, inversion symmetry in a solid is broken which, in addition to spin—orbit coupling, lifts the spin degeneracy 1. This effect is known as Rashba-type spin splitting, and the resulting Fermi surface consists of two pockets, an inner Fermi surface and an outer Fermi surface, which have a helical spin texture.
While the Rashba effect-inducing electric field is usually externally applied, such an electric field can also be produced at an interface with a polar discontinuity 2. Bulk LTO is a Mott insulator on the verge of a metal—insulator transition with a small band gap of 0. Metallicity in LTO can be induced by cation vacancies, excess oxygen, alkaline-earth doping of the rare-earth site, and epitaxial strain 8 , 9 , 10 , 11 , 12 , 13 , Furthermore, it has been shown that LTO juxtaposed with STO induces metallicity 15 , 16 and even superconductivity 17 at the interface, and it has been proposed that the system orders magnetically 18 , This metallicity is due to the fact that the epitaxial strain induces an electronic structure modification This includes electrical gating dependence of the electrical transport and analysis of the magnetoconductivity in the framework of weak anti-localization 21 , 22 , 23 , However, in this thickness regime, our previous studies 15 have demonstrated that the electrical transport is dominated by the metallic conduction inside the entire LTO film induced by the epitaxial strain.
