Transport Signatures of Fermi Surface Topology in BiTeI

The giant bulk Rashba spin-orbit coupling in BiTeI makes it not only an interesting spintronics system but also a host of an effect Dirac-like electronic structure of fundamental interest.~ As a function of lowering the Fermi level $E_{F} $ across the associated Dirac point ($E_{F} =0)$, the Fermi surface of BiTeI changes its topology: from a spindle-torus ($E_{F} >0)$ through a horn-torus ($E_{F} =0)$ to a ring-torus ($E_{F} <0)$. Here we report a systematic evolution of the magnetoresistance across these energy boundaries in high quality single crystals exhibiting Shubnikov-de Haas oscillations. We further discuss the physical origin of the detailed $E_{F} $/field/temperature dependences and remark on the relevance of this study to band crossings generally occurring in 3D systems.