Negative differential resistance and quantum oscillations in FeSb₂ with embedded antimony

We present a systematical study on single crystalline FeSb₂ using electrical transport and magnetic torque measurements at low temperatures. Nonlinear magnetic field dependence of Hall resistivity demonstrates a multi-carrier transport instinct of the electronic transport. Current-controlled negative differential resistance (CC-NDR) observed in current-voltage characteristics below~7 K is closely associated with the intrinsic transition~5 K of FeSb₂, which is, however, mediated by extrinsic current-induced Joule heating effect. The antimony crystallized in a preferred orientation within the FeSb₂ lattice in the high-temperature synthesis process leaves its fingerprint in the de Haas-Van Alphen (dHvA) oscillations, and results in the regular angular dependence of the oscillating frequencies. Nevertheless, possible existence of intrinsic non-trivial states cannot be completely ruled out. Our findings call for further theoretical and experimental studies to explore novel physics on flux-free grown FeSb₂ crystals.