Possible pressure-induced topological quantum phase transition in the nodal line semimetal ZrSiS

ZrSiS has recently gained attention due to its unusual electronic properties: nearly perfect electron-hole compensation, large, anisotropic magneto-resistance, multiple Dirac nodes near the Fermi level, and an extremely large range of linear dispersion of up to ∼2 eV. We have carried out a series of high pressure electrical resistivity measurements on single crystals of ZrSiS. Shubnikov-de Haas measurements show two distinct oscillation frequencies. For the smaller orbit, we observe that the phase of the oscillations changes by ∼0.5 between ∼0.16-0.5 GPa. This change in phase is accompanied by an abrupt decrease of the cross-sectional area of this Fermi surface. We attribute this change in phase to a possible topological quantum phase transition. The phase of the larger orbit exhibits a Berry phase of π and remains roughly constant up to ∼2.3 GPa. Resistivity measurements to higher pressures show no evidence for pressure-induced superconductivity to at least 20 GPa.