Weak antilocalization effect and high-pressure transport properties of ScPdBi single crystal

Half-Heusler compounds have attracted considerable attention due to their fantastic physical properties that include topological effects, Weyl fermions, unusual magnetism, and superconductivity. Herein, the transport properties of half-Heusler ScPdBi single crystals are studied across a wide temperature range and different magnetic fields. From the field-dependent magnetoresistance, we observe a clear weak antilocalization (WAL) effect below 200 K in the low magnetic-field region. The angle-dependent magnetoconductance and the ultralarge prefactor α extracted from the Hikami-Larkin-Nagaoka equation reveal that the WAL effect is a 3D bulk effect caused by strong spin-orbit coupling. We further studied the magnetotransport properties of the single crystal upon application of hydrostatic pressure and found that the energy gap of ScPdBi increases gradually as the hydrostatic pressure increases. Density functional theory calculations confirm that applying hydrostatic pressure decreases the lattice parameters and, consequently, enlarges the bandgap.