Two-Dimensional Superconductivity at the Titanium Sesquioxide Heterointerface.

Wang, Lijie; He, Wenhao; Huang, Guangyi; Xue, Huanyi; Zhang, Guanqun; Mu, Gang; Wu, Shiwei; An, Zhenghua et al. · ACS Nano · 2022

basic_science · Level V

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Abstract

The study of exotic superconductivity in two dimensions has been a central theme in the solid state and materials research communities. Experimentally exploring and identifying exotic, fascinating interface superconductors with a high transition temperature (<i>T</i><sub>c</sub>) are challenging. Here, we report an experimental observation of intriguing two-dimensional superconductivity with a <i>T</i><sub>c</sub> of up to 3.8 K at the interface between a Mott insulator Ti<sub>2</sub>O<sub>3</sub> and polar semiconductor GaN. At the verge of superconductivity, we also observe a striking quantum metallic-like state, demonstrating that it is a precursor to the two-dimensional superconductivity as the temperature is decreased. Our work shows an exciting opportunity to exploit the underlying, emergent quantum phenomena at the heterointerfaces via heterostructure engineering.