Large magnetoresistance in the iron-free pnictide superconductor LaRu₂P₂

The magnetoresistance (MR) of iron pnictide superconductors is often dominated by electron-electron correlations and deviates from theH²or saturating behaviors expected for uncorrelated metals. Contrary to similar Fe-based pnictide systems, the superconductor LaRu₂P₂(T_c= 4 K) shows no enhancement of electron-electron correlations. Here we report a non-saturating MR deviating from theH²or saturating behaviors in LaRu₂P₂. We present results in single crystals of LaRu₂P₂, where we observe a MR followingH^1.3up to 22 T. We discuss our result by comparing the bandstructure of LaRu₂P₂with that of Fe based pnictide superconductors. The different orbital structures of Fe and Ru leads to a 3D Fermi surface with negligible bandwidth renormalization in LaRu₂P₂, that contains a large open sheet over the whole Brillouin zone. We show that the large MR in LaRu₂P₂is 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 LaRu₂P₂.