Probing surface electronic properties of a patterned conductive STO by reactive ion etching

Pure Spin Currents Driven by Colossal Spin–Orbit Coupling on Two-Dimensional Surface Conducting SrTiO3

“…Conducting surfaces of STO (oxygen vacancy mediated) have electron mean free path lengths up to 500 nm . From a previous study on the surface conductivity of STO via Ar plasma treatment, we demonstrated λ e ∼ 100 nm. In this work, we use a channel width of 1 μm with λ e ≪ w ≪ λ s in the spin Hall regime where the nonlocal resistance change is , where γ is the spin Hall angle, defined as the spin Hall conductivity divided by the charge conductivity (or, on the conducting surface, and R sq is the sheet resistance of STO.…”

“…Substrates are cleaned by acetone, ethanol, and deionized water with ultrasonic treatment. Ar plasma treatment is used for creating oxygen vacancies on the STO surface, which leads to conductive surface . In situ Ar plasma (50 W power) treatment is applied to the STO surface for 30–60 min at a pressure of 30 mTorr with an Ar atmosphere.…”

“…The functional oxide SrTiO 3 (STO) has been shown in recent years to exhibit a wide-range of fascinating behaviors, including interface magnetism; − two-dimensional (2D) surface conductivity; − a temperature- and magnetic-field-tunable dielectric constant ( k ); a strong thermoelectric Seebeck coefficient; ferroelectricity; , a temperature transition from paraelectricity to ferroelectricity at 45 K; ,− quantum paraelectricity below 4 K; ,− and superconductivity below 0.35 K . Of these, 2D surface conductivity is a rapidly developing area and has been demonstrated at Al 2 O 3 /SrTiO 3 , LaAlO 3 /SrTiO 3 (LAO/STO), LaTiO3/SrTiO 3 , and yttria-stabilized zirconia/SrTiO, interfaces. − , The STO surface transforms to a metallic-state with mobilities up to 50 000 cm 2 /V·s at low temperature , through the creation of oxygen vacancies using a beam of Ar ions − or doping with Nb or La, which substitute the Ti and Sr sites, respectively. − ,− …”

“…The theoretical reports predicted about the intrinsic spin Hall conductivity related with strains but did not consider extrinsic effect induced by such as defects. Note that our Ar plasma treated two-dimensional conductive STO surface creates a high concentration of defects including oxygen vacancies. , Thus, the spin Hall constant will include contributions from the extrinsic spin orbit coupling mechanism (or coexistance of intrinsic and extrinsic) induced by impurities and point defects.…”

Rewritable High-Mobility Electrons in Oxide Heterostructure of Layered Perovskite/Perovskite

“…In contrast, the oxygen-vacancy-induced conductivity is expected to have greater tunability since oxygen vacancies are rather mobile and can be modulated after growth easily. High-temperature reduction in a vacuum or in hydrogen, , low-energy Ar ion bombardment, reactive ion etching, and surface scratching have been employed to tune the oxygen vacancies and carrier concentrations in bulk STO or STO-based heterostructures. Nonetheless, the electron mobility values obtained by these methods are not very high, and the sample surface may be damaged in some cases.…”