Large magnetoresistance in the iron-free pnictide superconductor LaRu$_2$P$_2$

Abstract

The magnetoresistance of iron pnictide superconductors is often dominated by electron-electron correlations and deviates from the H 2 or saturating behaviors expected for uncorrelated metals.Contrary to similar Fe-based pnictide systems, the superconductor LaRu 2 P 2 (T c = 4 K) shows no enhancement of electron-electron correlations. Here we report a non-saturating magnetoresistance deviating from the H 2 or saturating behaviors in LaRu 2 P 2 . We have grown and characterized high quality single crystals of LaRu 2 P 2 and measured a magnetoresistance following H 1.3 up to 22 T. We discuss our result by comparing the bandstructure of LaRu 2 P 2 with Fe based pnictide superconductors. The different orbital structures of Fe and Ru leads to a 3D Fermi surface with negligible bandwidth renormalization in LaRu 2 P 2 , that contains a large open sheet over the whole Brillouin zone. We show that the large magnetoresistance in LaRu 2 P 2 is unrelated to the one obtained in materials with strong electron-electron correlations and that it is compatible instead with conduction due to open orbits on the rather complex Fermi surface structure of LaRu 2 P 2 .