Enhanced superconductivity in TiO epitaxial thin films

Authors

Chao Zhang, University of Science and Technology of China
Feixiang Hao, University of Science and Technology of China
Guanyin Gao, University of Science and Technology of China
Xiang Liu, University of Science and Technology of China
Chao Ma, University of Science and Technology of China
Yue Lin, University of Science and Technology of China
Yuewei Yin, University of Nebraska - LincolnFollow
Xiaoguang Li, Institute of Solid State PhysicsFollow

Document Type

Article

Date of this Version

2017

Citation

npj Quantum Materials (2017) 2:2 ; doi:10.1038/s41535-016-0006-3

Comments

© The Author(s) 2017. This work is licensed under a Creative Commons Attribution 4.0 International License.

Abstract

Titanium oxides have many fascinating optical and electrical properties, such as the superconductivity at 2 K in cubic titanium monoxide (TiO) polycrystalline bulk. However, the lack of TiO single crystals or epitaxial films has prevented systematic investigations on its superconductivity. Here, we report the basic superconductivity characterizations of cubic TiO films epitaxially grown on (0001)-oriented α-Al₂O₃ substrates. The magnetic and electronic transport measurements confirmed that TiO is a type-II superconductor and the recorded high T_c is about 7.4 K. The lower critical field (Hc1) at 1.9 K, the extrapolated upper critical field Hc2(0), and coherence length are about 18 Oe, 13.7 T, and 4.9 nm, respectively. With increasing pressure, the value of Tc shifts to lower temperature while the normal state resistivity increases. Our results on the superconducting TiO films confirm the strategy to achieve higher T_c in the epitaxial films, which may be helpful for finding more superconducting materials in various related systems.