Pressure-Induced Superconductivity in Mineral Calaverite AuTe2

The pressure dependences of resistivity and ac susceptibility have been measured in the mineral calaverite AuTe${}_2$. Resistivity clearly shows a first-order phase transition into a high-pressure phase, consistent with the results of a previous structural analysis. We found zero resistivity and a diamagnetic shielding signal at low temperatures in the high-pressure phase, which clearly indicates the appearance of superconductivity. Our experimental results suggest that bulk superconductivity appears only in the high-pressure phase. For AuTe${}_2$, the highest superconducting transition temperature under pressure is $T_{\mathrm{c}}$ = 2.3 K at 2.34 GPa; it was $T_{\mathrm{c}}$ = 4.0 K for Pt-doped (Au${}_{0.65}$Pt${}_{0.35}$)Te${}_2$. The difference in $T_{\mathrm{c}}$ between the two systems is discussed on the basis of the results obtained using the band calculations and McMillan’s formula.