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Abstract

The advent of nodal-line semimetals, i.e., systems in which the conduction and valence bands cross each other along a closed trajectory (line or loop) inside the Brillouin zone, has opened up a new arena for the exploration of topological condensed matter in which, due to a vanishing density of states near the Fermi level, electron correlation effects alsomay play an important role. Despite this conceptual richness, however, material realization of nodal-line (loop) fermions is rare with PbTaSe2, ZrSiS, and PtSn4 as the only promising known candidates. Here we report the synthesis and physical properties of a semimetal PdScc that is isostructural with PtSn4 yet possesses quasiparticles with significantly enhanced effective masses. In addition, PdSn4 displays an unusual polar angular magnetoresistance which, at a certain field orientation, varies linearly with fields up to 55 T. Our paper suggests that, in association with its homologue PtSn4 whose low-lying excitations recently were claimed to possess Dirac nodal arcs, PdSn4 may be a promising candidate in the search for novel topological states with enhanced correlation effects.