Large magnetoresistance in the iron-free pnictide superconductor LaRu₂P₂

Abstract

The magnetoresistance (MR) 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 LaRu2P2 (T c = 4 K) shows no enhancement of electron–electron correlations. Here we report a non-saturating MR deviating from the H 2 or saturating behaviors in LaRu2P2. We present results in single crystals of LaRu2P2, where we observe a MR following H 1.3 up to 22 T. We discuss our result by comparing the bandstructure of LaRu2P2 with 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 LaRu2P2 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 LaRu2P2.

Superconductivity and band structure of layered AuSn$_4$

“…To explain the linear and nonsaturating behavior of the MR AuSn 4 we can think of a linearly dispersing portion of the bandstructure, charge density waves, a complex distribution of paths for the passage of currents or open orbits [7][8][9][10][58][59][60][61][62][63][64][65][66][67][68][69][70][71][72][73]. We do not find portions with a linear dispersion close to the Fermi level in the band structure.…”

Band structure, superconductivity, and polytypism in AuSn4

“…Our calculations show that the Fermi surface of AuSn 4 contains five large and highly anisotropic sheets (Fig. 10 We can also consider other sources for a nonsaturating MR, such as a linearly dispersing portion of the band structure, charge density waves, open orbits, or disorder [7][8][9][10]10,[75][76][77][78][79][80][81][82][83][84][85][86][87][88][89][90]. We do not find portions with a linear dispersion close to the Fermi level in the band structure.…”