Contrasts in electron correlations and inelastic scattering between LiFeP and LiFeAs revealed by charge transport

By using high-quality single crystals, we quantitatively compare the transport properties between LiFeP and LiFeAs superconductors with compensated electron and hole carriers. The low-temperature resistivity follows the Fermi-liquid AT2 dependence with a factor of ∼3 difference in the coefficient A. This highlights weaker electron correlations in LiFeP, which is consistent with its ∼70 times lower upper critical field than that of LiFeAs. Our analysis of the magnetotransport data indicates that in LiFeP, the electron carriers with lighter masses exhibit stronger temperature dependence of inelastic scattering rate than the holes, which is the opposite to the LiFeAs case. This stark difference in the band-dependent inelastic scattering may be relevant to the recently reported contrasting superconducting gap structures in these two superconductors.