Development of High-Temperature Superconductivity in a Copper-oxygen Monolayer
P-C. Chiang1*, J-C. Yang2, Y-H.Chu2,3,4, J-Y. Lin1
1Institute of Physics, National Chiao Tung University, Hsinchu 30010, Taiwan
2Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan
3Department of Physics, National Chiao Tung University, Hsinchu 30010, Taiwan
4Institute of Physics, Academia Sinica, Nankang 11529, Taiwan
* presenting author:蔣平志,
The transition metal complex oxides possess versatile functionalities because of the charming interplays between spin, charge, orbit, and lattice degrees of freedom. The strongly correlation effects are of great importance for understanding the intriguing properties in complex oxide systems, such as metal-insulator transition, high-temperature superconductivity, colossal magnetoresistance, orbital ordering and so on. In the past decade, the appealing functionalities at interfaces have received increasing interests since the boundary between different materials might offer an elegant platform for novel emergent phenomena.
In this study, a new type of functional two-dimensional interface composed of copper-oxygen monolayer is grown and demonstrated via pulsed laser deposition. By using the atomically flat TiO₂-terminated SrTiO₂ substrate and reflection high-energy electron diffraction (RHEED), the deposited SrCuO₂ can be controlled in precise mono-layer thick. This one-atomic-layer structure effectively generates a two-dimensional CuO₂ mono-layer, serving as a model system for understanding the correlated interplays and for exploring novel functionalities within an ultra-thin layer. Our atomic force spectroscopy has confirmed the atomic-flat topography, indicating a successful epitaxial growth. We propose to investigate the detailed physical properties of CuO₂ mono-layer. The charge transfer in the CuO₂ mono-layer can be significantly enhanced by increasing carrier concentration at the interface, resulting in the tunable conductivity in the mono-layer system. The ultra-thin mono-layers can exhibit promising potentials in revealing numerous undiscovered physical properties, as well as in developing next generation electronic devices.

Keywords: high-temperature superconductivity