Reversible superconductor-insulator transition in LiTi2O4 induced by Li-ion electrochemical reaction

• Published in: Scientific reports Vol. 5; no. 1; p. 16325
• Main Authors: Yoshimatsu, K., Niwa, M., Mashiko, H., Oshima, T., Ohtomo, A.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 06.11.2015; Nature Publishing Group
• Subjects: 639/301/119/1003; 639/766/119/544; 639/766/25; Crystal structure; Humanities and Social Sciences; multidisciplinary; Oxidation; Oxides; Science; Temperature effects
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep16325

Transition metal oxides display various electronic and magnetic phases such as high-temperature superconductivity. Controlling such exotic properties by applying an external field is one of the biggest continuous challenges in condensed matter physics. Here, we demonstrate clear superconductor-insulator transition of LiTi 2 O 4 films induced by Li-ion electrochemical reaction. A compact electrochemical cell of pseudo-Li-ion battery structure is formed with a superconducting LiTi 2 O 4 film as an anode. Li content in the film is controlled by applying a constant redox voltage. An insulating state is achieved by Li-ion intercalation to the superconducting film by applying reduction potential. In contrast, the superconducting state is reproduced by applying oxidation potential to the Li-ion intercalated film. Moreover, superconducting transition temperature is also recovered after a number of cycles of Li-ion electrochemical reactions. This complete reversible transition originates in difference in potentials required for deintercalation of initially contained and electrochemically intercalated Li + ions.