  We theoretically investigate the phase of the de Haas - van Alphen
oscillations in topological line-node semimetals. In these semimetals the
chemical potential of charge carriers can essentially depend on the magnetic
field, and this dependence changes the phase of the oscillations as compared to
the phase in a three-dimensional metal with a band-contact line. Our results
elucidate recent experimental data on the Berry phase for certain electron
orbits in ZrSiS, ZrSiTe, and ZrSiSe.
