Negative differential resistance and quantum oscillations in FeSb_2 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 currentvoltage 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 FeSb_2 crystals.

Physical Properties of Half-Heusler Antiferromagnet MnPtSn Single Crystal

We report the growth of ternary half-Heusler MnPtSn single crystals and detailed study on its structural and physical properties.MnPtSn single crystal has a larger lattice parameter than that in polycrystal and it exhibits antiferromagnetism with transition temperature TN at about 215 K,distinctly different from the ferromagnetism of MnPtSn polycrystal.Hall resistivity measurement indicates that the dominant carriers are hole-type and the nearly temperature-independent carrier concentration reaches about 2.86×10^22 cm^-3 at 5 K.Moreover,the carrier mobility is also rather low(4.7 cm^2·V^-1s^-1 at 5 K).The above results strongly suggest that the significant Mn/Sn anti-site defects,i.e.,the content of Mn in MnPtSn single crystal,play a vital role on structural,magnetic and transport properties.