Quasi-two-dimensional electron gas and weak antilocalization at the interface of SrTaO3/KTaO3 heterostructures

As a potential system for realizing strong spin-orbit coupling (SOC), $5d\text{\ensuremath{-}}A\mathrm{Ta}{\mathrm{O}}_{3}$ perovskite oxides have recently received extensive attention. This study presents ${\mathrm{SrTaO}}_{3}/\mathrm{KTa}{\mathrm{O}}_{3} 5d\text{\ensuremath{-}}5d$ heterostructures with thickness-induced crossover from quasi-two-dimensional (2D) to three-dimensional (3D) transport behaviors. The sheet carrier concentration and carrier mobility of the system depend on the ${\mathrm{SrTaO}}_{3}$ film thickness. The highest mobility of $430\phantom{\rule{0.16em}{0ex}}\mathrm{c}{\mathrm{m}}^{2}\phantom{\rule{0.16em}{0ex}}{\mathrm{V}}^{\ensuremath{-}1}\phantom{\rule{0.16em}{0ex}}{\mathrm{s}}^{\ensuremath{-}1}$ is observed for the heterostructure with a 16-nm-thick ${\mathrm{SrTaO}}_{3}$ film, which comprises coexisting 2D and 3D transport components. Weak antilocalization, anisotropic magnetoresistance, and the plane Hall effect are observed, which robustly confirm the existence of strong SOC in the heterostructure. The tunable transport and strong correlation effect make the ${\mathrm{SrTaO}}_{3}/\mathrm{KTa}{\mathrm{O}}_{3}$ heterostructure not only a suitable platform for investigating basic physical phenomena but also a potential material candidate for future spin devices.