Enhanced superconductivity in Sr2CuO4−v

A critical review of previous investigations of the superconductivity with enhanced Tc ∼ 95 K found in Sr2CuO4−v shows that new physics occurs in a highly overdoped region of the cuprate phase diagram. Moreover, evidence is adduced from the literature that 30% of the oxygen sites in the CuO2 layers are vacant; a conclusion which is at odds with the universally made assumption that superconductivity originates in stoichiometric CuO2 layers. While further research is needed in order to identify the pairing mechanism(s) responsible for the enhanced Tc, we suggest possible candidates.