Tunable superconductivity in parent cuprate Pr2CuO4±δ thin films**Project supported by the National Key Basic Research Program of China (Grant Nos. 2015CB921000, 2016YFA0300301, 2017YFA0303003, and 2018YFB0704100), the National Natural Science Foundation of China (Grant Nos. 11674374 and 11474338), the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences (Grant No. QYZDB-SSW-SLH008), the Strategic Priority Research Program of the

Abstract

We studied the role of oxygen in Pr2CuO4±δ thin films fabricated by the polymer assisted deposition method. The magnetoresistance and Hall resistivity of Pr2CuO4±δ samples were systematically investigated. It was found that with decreasing oxygen content, the low-temperature Hall coefficient (RH) and magnetoresistance changed from negative to positive, similar to those with the increase of Ce-doped concentration in CexCuO4 (R=La, Nd, Pr, Sm, Eu). In addition, we observed that the dependence of the superconducting critical temperature Tc with RH for the Pr2−xCexCuO4 perfectly overlapped with that of Pr2CuO4±δ. These findings point to the fact that the doped electrons induced by the oxygen removal are responsible for the superconductivity of the -phase parent compounds.