Coexistence of two-dimensional and three-dimensional Shubnikov–de Haas oscillations in Ar+-irradiated KTaO3.

We report electron doping in the surface vicinity of KTaO3 by inducing oxygen vacancies via Ar+ irradiation. The doped electrons have high mobility (>104 cm2/V s) at low temperatures, and exhibit Shubnikov-de Haas oscillations with both two- and three-dimensional components. A disparity of the extracted in-plane effective mass, compared to the bulk values, suggests mixing of the orbital characters. Our observations demonstrate that Ar+ irradiation serves as a flexible tool to study low-dimensional quantum transport in 5d semiconducting oxides. [ABSTRACT FROM AUTHOR]