Similarly, ErPdBi has been reported to show the coexistence of antiferromagnetism ( T N = 1.06 K) and superconductivity ( T c = 1.22 K) and hence acclaimed as a new platform for the research of the reciprocity of magnetic order, superconductivity and nontrivial topological states 31. In turn, CePdBi has shown some features of incipient superconductivity ( T c = 1.3 K) emerging in the antiferromagnetic state ( T N = 2 K) and a hypothesis on topological character of the compound has also been formulated 30. Recently, diamagnetic YPdBi has been reported to exhibit large linear magnetoresistance (LMR) and Shubnikov-de Haas (SdH) quantum oscillations at low temperatures and its nontrivial topological nature has been evaluated 29. Most of them have been characterized as local-moment antiferromagnets (with Néel temperatures T N = 2–13 K) with electrical properties characteristic of semimetals or narrow-band semiconductors. Magnetic and transport behaviors of these compounds have been first investigated on polycrystalline samples 25, 26, 27, 28. Potentially, the rare-earth palladium-bearing bismuthides REPdBi are equally interesting from the point of view of topological and superconducting properties. Besides, the content of magnetic rare-earth may bring about other properties, such as long-range antiferromagnetic ordering or heavy fermion behavior 24. In this context, the superconductivity recently found in the bismuthides REPtBi: LaPtBi ( T c = 0.9 K) 19, LuPtBi ( T c = 1.0 K) 20 and YPtBi ( T c = 0.77 K) 21, 22, 23 appears most attracting. 17), new TS materials are sought extensively among low-carrier-density semiconductors, whose Fermi surfaces are centered around time-reversal-invariant momenta 18. Since it remains problematic to clarify the nature of the surface Majorana fermions in the inhomogeneous crystals of Cu xBi 2Se 3 (Ref. The first theoretically forecasted and experimentally discovered TS was Bi 2Se 3 doped with Cu atoms 15, 16. Topological superconductor (TS) is a material characterized by protected Majorana surface states and bulk consisting of mixed-parity Cooper-pair states 13, 14. In result, the rare-earth ( RE) based half-Heusler compounds ( REPdBi, REPtBi, REPdSb, REPtSb) may possibly form the biggest group of the three-dimensional (3D) TIs.Īfter the discovery of the 3D TI systems, a quest for superconductivity in materials with the non-trivial topology of electron bands started due to their potential applications in topological quantum computing 10, 11, 12. In contrast to two-dimensional (2D) TIs, like HgTe, some of half-Heusler phases possess not only band inversion at an odd number of time-reversal-invariant momenta, but also may have a bulk band-gap opening under uniaxial pressure, which lowers the crystal symmetry 9. Such properties open new prospects for spintronic applications. These surface states are theoretically described as massless Dirac fermions with linear dispersion and lifted spin-degeneracy. Topological insulators (TI) constitute a new class of materials, which are insulating in the bulk, but at the same time their surface states are protected from backscattering by Z 2 topology 6, 7, 8. Recent ab initio electronic structure calculations have predicted that several dozen of half-Heusler compounds, due to a strong spin-orbit coupling, have inverted bands requisite for topological properties 3, 4, 5. Large family of half-Heusler compounds that crystallize in a noncentrosymmetric cubic MgAgAs-type structure attracts much attention due to their remarkable magnetic and electrical transport properties 1, 2. 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. Below 10 K, it is accompanied by Shubnikov-de Haas oscillations. The linear magnetoresistance is observed up to room temperature. Above about 1.5 T, the magnetoresistance becomes linear and does not saturate in fields up to 9 T. The magnetoresistance is huge and clearly shows a weak antilocalization effect in small magnetic fields. 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. Although superconducting state is clearly reflected in the electrical resistivity and magnetic susceptibility data, no corresponding anomaly can be seen in the specific heat. 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. 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.
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