Shubnikov - de Haas oscillations, weak antilocalization effect and large linear magnetoresistance in the putative topological superconductor LuPdBi

摘要

We present electronic transport and magnetic properties of single crystals of semimetallic half-Heusler phase LuPdBi, having theoretically predicted band inversion requisite for nontrivial topological properties. The compound exhibits superconductivity below a critical temperature T _c = 1.8?K, with a zero-temperature upper critical field B _c2 ≈ 2.3?T. Although superconducting state is clearly reflected in the electrical resistivity and magnetic susceptibility data, no corresponding anomaly can be seen in the specific heat. Temperature dependence of the electrical resistivity suggests existence of two parallel conduction channels: metallic and semiconducting, with the latter making negligible contribution at low temperatures. The magnetoresistance is huge and clearly shows a weak antilocalization effect in small magnetic fields. Above about 1.5?T, the magnetoresistance becomes linear and does not saturate in fields up to 9?T. The linear magnetoresistance is observed up to room temperature. Below 10?K, it is accompanied by Shubnikov-de Haas oscillations. Their analysis reveals charge carriers with effective mass of 0.06 m_e and a Berry phase very close to π , expected for Dirac-fermion surface states, thus corroborating topological nature of the material.