  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.
