A termination-insensitive and robust electron gas at the heterointerface of two complex oxides

• Meng Zhang, Kai Du, Tianshuang Ren, He Tian*, Ze Zhang, Harold Y. Hwang & Yanwu Xie*

The single-crystal SrTiO3 (001) has two different surface terminations, TiO2 and SrO. One most remarkable observation in previous studies is that only the heterointerfaces with TiO2-terminated SrTiO3, which usually combines with polar oxides such as LaAlO3, host an electron gas. Here we show that a robust electron gas can be generated between a non-polar oxide, CaHfO3, and SrTiO3 (001) with either termination. Unlike the well-known electron gas of LaAlO3/SrTiO3, the present one of CaHfO3/SrTiO3 essentially has no critical thickness of CaHfO3, can survive a long-time oxygen annealing at high temperature, and its transport properties are stable under exposure to water and other polar solvents. By electrostatic gating through CaHfO3, field-effect devices are demonstrated using CaHfO3/SrTiO3 heterointerfaces with both terminations. These results show that the electron gas reported in the present study is unique and promising for applications in oxide electronics.

Nature Communicationsvolume 10, Article number: 4026 (2019)

The published article is available at https://www.nature.com/articles/s41467-019-12036-5