Coexistence of two- and three-dimensional Shubnikov-de Haas oscillations in Ar^+ -irradiated KTaO_3

TL;DR

This study demonstrates that Ar^+ -irradiation induces high-mobility electron doping in KTaO_3, revealing coexistence of 2D and 3D Shubnikov-de Haas oscillations and providing insights into low-dimensional quantum transport in 5d oxides.

Contribution

It shows that Ar^+ -irradiation can be used to controllably induce and study low-dimensional quantum transport phenomena in KTaO_3.

Findings

High electron mobility (>10^4 cm^2/Vs) at low temperatures.

Observation of both 2D and 3D Shubnikov-de Haas oscillations.

Disparity in effective mass indicating orbital mixing.

Abstract

We report the electron doping in the surface vicinity of KTaO_3 by inducing oxygen-vacancies via Ar^+ -irradiation. The doped electrons have high mobility (> 10^4 cm^2/Vs) 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.