Nodal-line driven anomalous susceptibility in ZrSiS

Abstract: We demonstrate a unique approach to test the signature of the nodal-line physics by thermodynamic methods. By measuring magnetic susceptibility in ZrSiS we found an intriguing temperature-driven crossover from dia- to paramagnetic behavior. We show that the anomalous behavior represents a real thermodynamic signature of the underlying nodal-line physics through the means o chemical pressure (isovalent substitution of Zr for Hf), quantum oscillations, and theoretical model ng. The anomalous part of the susceptibility is orbital by nature, and it arises due to the vicinity of the Fermi level to a degeneracy point created by the crossing of two nodal lines. Furthermore, an unexpected Lifshitz topological transition at the degeneracy point is revealed by tuning the Ferm level. The present findings in ZrSiS give a new and attractive starting point for various nodal-lin physics-related phenomena to be tested by thermodynamic methods in other related materials.