Magnetotransport in Sr 3 PbO antiperovskite

Novel topological phenomena are anticipated for three-dimensional (3D) Dirac electrons. The magnetotransport properties of cubic ${\mathrm{Sr}}_{3}\mathrm{PbO}$ antiperovskite, theoretically proposed to be a 3D massive Dirac electron system, are studied. The measurements of Shubnikov--de Haas oscillations and Hall resistivity indicate the presence of a low density ($\ensuremath{\sim}1\ifmmode\times\else\texttimes\fi{}{10}^{18}\phantom{\rule{0.16em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}3}$) of holes with an extremely small cyclotron mass of $0.01--0.06{m}_{e}$. The magnetoresistance $\mathrm{\ensuremath{\Delta}}{\ensuremath{\rho}}_{xx}(B)$ is linear in magnetic field $B$ with the magnitude independent of temperature. These results are fully consistent with the presence of 3D massive Dirac electrons in ${\mathrm{Sr}}_{3}\mathrm{PbO}$. The chemical flexibility of the antiperovskites and our findings in the family member ${\mathrm{Sr}}_{3}\mathrm{PbO}$ point to their potential as a model system in which to explore exotic topological phases.