Charge-carrier-type controlled superconducting dome in ZrN_xO_y films

Modifying the normal state charge carriers and the related Fermi surface can significantly affect a material's superconducting state. The recently discovered superconducting dome as a function of chemical concentration in transition metal nitrides provides a promising platform for achieving such control. However, this effort was hindered by synthesis techniques that cannot stabilize the material's structure in the presence of a significant number of nitrogen vacancies. In this study, we employed oxygen-assisting nitrogen gas flow with radio frequency magnetron sputtering to stabilize the crystal structure of nitrogen-deficient zirconium nitride thin films and explore the impact of normal state charge carrier types on the superconducting state. Our electrical and thermoelectrical transport measurements indicate a fine-tuning of the superconducting transition temperature, Tc, through a shift from hole-type to electron-type charge carriers. Additionally, a concurrent strain release, reflected in the change of the film's crystal orientation, is observed in the process.