High-entropy-alloy-type (HEA-type) compound superconductors have been drawing
much attention as a new class of exotic superconductors with local structural
inhomogeneity. NaCl-type (Ag,In,Sn,Pb,Bi)Te is a typical HEA-type
superconductor, but the carrier doping mechanism had been unclear. In this
study, we synthesized (Ag,In,Sn,Pb,Bi)Te with various In concentration using
high-pressure synthesis: the studied system is (AgSnPbBi)(1-x)/4InxTe (x =
0-0.4). Single-phase samples were obtained for x = 0-0.3. A semiconductor-like
temperature dependence of resistivity was observed for x = 0, while
superconductivity appeared for the In-doped samples. The highest transition
temperature (Tc) was 3.0 K for x = 0.3. The Seebeck coefficient decreases with
increase of x, which suggests that In3+ generates electron carriers in
(AgSnPbBi)(1-x)/4InxTe. Tuning of carrier concentration and superconducting
properties of (Ag,In,Sn,Pb,Bi)Te would be useful for further investigation of
exotic superconductivity in the HEA-type compound.Comment: 11 pages, 4 figures, 1 tabl