  High quality half-Heusler single crystals of LuPtSb have been synthesized by
a Pb flux method. The temperature dependent resistivity and Hall effects
indicate that the LuPtSb crystal is a p-type gapless semiconductor showing a
transition from semiconducting to metallic conducting at 150 K. Moreover, a
weakly temperature-dependent positive magnetoresistance (MR) as large as 109 %
and high carrier mobility up to 2950 cm2/Vs are experimentally observed at
temperatures below 150 K. The low-field MR data shows evidence for weak
antilocalization (WAL) effect at temperatures even up to 150 K. Analysis of the
temperature and angle dependent magnetoconductance manifests that the WAL
effect originates from the bulk contribution owing to the strong spin-orbital
coupling.
