  We have systematically grown large single crystals of layered compound
beta-PdBi2, both the hole-doped PdBi2-xPbx and the electron-doped NaxPdBi2, and
studied their magnetic and transport properties. Hall-effect measurement on
PdBi2, PdBi1.8Pb0.2, and Na0.057PdBi2 shows that the charge transport is
dominated by electrons in all of the samples. The electron concentration is
substantially reduced upon Pb-doping in PdBi2-xPbx and increased upon
Na-intercalation in NaxPdBi2, indicating the effective hole-doping by Pb and
electron-doping by Na. We observed a monotonic decrease of superconducting
transition temperature (Tc) from 5.4K in undoped PdBi2 to less than 2K for x >
0.35 in hole-doped PdBi2-xPbx. Meanwhile, a rapid decrease of Tc with the Na
intercalation is also observed in the electron-doped NaxPdBi2, which is in
disagreement with the theoretical expectation. In addition, both the
magnetoresistance and Hall resistance further reveal evidence for a possible
spin density wave (SDW)-like transition below 50K in the Na-intercalated PdBi2
sample. The complete phase diagram is thus established from hole-doping to
electron-doping. Meanwhile, high pressure study of the undoped PdBi2 shows that
the Tc is linearly suppressed under pressure with a dTc/dP coefficient of
-0.28K/GPa.
