Large magnetoresistance in the iron-free pnictide superconductor LaRuP.

The magnetoresistance (MR) of iron pnictide superconductors is often dominated by electron-electron correlations and deviates from theor saturating behaviors expected for uncorrelated metals. Contrary to similar Fe-based pnictide systems, the superconductor LaRuP(= 4 K) shows no enhancement of electron-electron correlations. Here we report a non-saturating MR deviating from theor saturating behaviors in LaRuP. We present results in single crystals of LaRuP, where we observe a MR followingup to 22 T. We discuss our result by comparing the bandstructure of LaRuPwith 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 LaRuP, that contains a large open sheet over the whole Brillouin zone. We show that the large MR in LaRuPis 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 LaRuP.