Growth and Characterization of Pure and Sm-Doped Sb2Te3 Single Crystal

Here, we report single crystalline growth, characterization, and magneto-transport study of SmxSb2-xTe3 (x = 0 and 0.05) topological insulator. Single crystals were grown by solid state reaction by following self-flux method. Phase purity, single crystalline growth, and layered structure were confirmed by X-ray diffraction (XRD) spectra and scanning electron microscopy (SEM) images. Elemental composition was extracted by using energy dispersive X-ray analysis (EDAX) and Raman spectra were obtained at room temperature to study the vibrational modes or grown SmxSb2-xTe3 single crystal. Sb2Te3 shows the ≈ 550% magnetoresistance at 12 Tesla and 2 K, which further reduced to ≈ 210% at 12 Tesla and 2 K by doping of Sm in Sb2Te3. A v-type cusp was observed in low magnetic field regime (≤ 1 Tesla) at all measured temperatures for both crystals, which was analyzed by using Hikami-Larkin-Nagaoka (HLN) equation. The extracted parameters α and phase coherence length (Lφ) show the presence of weak anti-localization effect in both crystals. Furthermore, to study the effect of temperature and magnetic field on conduction, field-dependent quadratic term and linear term were added in conventional HLN model which explains the contribution of quantum scattering and bulk contribution in magnetoconductivity, respectively.