Pressure evolution of quantum oscillations and electronic structure in ZrSiS

This work presents a systematic study of the pressure evolution of the electronic structure of ZrSiS using bulk magnetotransport measurements under hydrostatic pressure and first-principles calculations. Magnetoresistance measured at four pressure points (0.25, 0.47, 1.55, and 2.10 GPa) exhibits clear Shubnikov-de Haas oscillations characterized by five dominant frequencies, ${F}_{\ensuremath{\alpha}}=17$, ${F}_{\ensuremath{\beta}}=37$, ${F}_{\ensuremath{\gamma}}=93$, ${F}_{\ensuremath{\delta}}=138$, and ${F}_{\ensuremath{\epsilon}}=242\phantom{\rule{0.16em}{0ex}}\mathrm{T}$, which remain nearly unchanged with increasing pressure. To probe the pressure evolution of the electronic states, the Berry phase $({\mathrm{\ensuremath{\Phi}}}_{\mathrm{B}})$ was extracted from Landau level fan diagram analyses. The extracted ${\mathrm{\ensuremath{\Phi}}}_{\mathrm{B}}$ values for the $\ensuremath{\alpha}$ and $\ensuremath{\epsilon}$ orbits show a systematic evolution with pressure, changing from values close to $\ensuremath{\pi}$ at low pressure toward values approaching zero above $\ensuremath{\sim}0.47$ GPa, suggesting a possible change in the electronic topology near this pressure. To further examine the evolution of the band topology, we calculated the topological invariants calculations. The results suggest nontrivial states at low pressures and a tendency toward trivial states at higher pressures, consistent with the experimentally observed evolution of the Berry phase. To further investigate the underlying electronic structure, first-principles calculations were performed up to 16 GPa. The calculated band structures reveal multiple Dirac crossings near the Fermi level derived primarily from Zr $d$ and S $p$ orbitals, which remain robust under pressure. Phonon dispersion calculations show no imaginary modes up to 16 GPa, confirming the dynamical stability of ZrSiS under hydrostatic compression. The combined experimental and theoretical results indicate that pressure modifies the electronic states without a pronounced reconstruction of the Fermi surface, highlighting the role of subtle changes in the electronic structure. These findings provide insight into pressure-driven electronic evolution in nodal-line semimetals and related quantum materials.