Zero resistivity above 150K in HgBa₂Ca₂Cu ₃O_8+δ at high pressure

We measured the electrical resistivity of a HgBa₂Ca ₂Cu₃O_8+δ (Hg-1223) polycrystalline sample under high pressure. Owing to the improved sample quality and the nearly hydrostatic pressure, we successfully observed zero resistivity, which is the unambiguous signature of superconductivity, up to the unprecedented temperature of 153.0K at 15 GPa. This temperature surpasses the previous records by more than 10 K. Referring to the experimental results, we established the exact pressure (P) vs superconducting transition temperature (T_c) relationship. T_c increases with P up to 15 GPa, suggesting the possibility of further enhancement of T_c at higher pressures.