Superconductivity in In-doped AgPbBiTe3 compounds synthesized by high-pressure synthesis

NaCl-type metal tellurides (MTe) have been widely studied due to unique physical properties. We investigated the In-doping effects on structural and physical properties of Na-Cl type (AgPbBi)(1-x)/3InxTe and the superconducting properties of the In-doped samples. Polycrystalline samples with x = 0-0.5 were synthesized by utilizing high-pressure synthesis. For x = 0.2-0.5, superconductivity was observed in magnetization measurements, where the highest transition temperature (Tc) was 2.8 K for x = 0.4. We measured specific heat for x = 0.4 and confirmed the bulk nature of the superconductivity. The evolution of the Seebeck coefficient and lattice constant by In doping suggests that In valence state is In+3, and the In doping generates electron carriers in the (AgPbBi)(1-x)/3InxTe system.