The Sb 2 Te 3 crystals are grown using the conventional self flux method via solid state reaction route, by melting constituent elements (Sb and Te) at high temperature (850˚C), followed by slow cooling (2˚C/hour). As grown Sb 2 Te 3 crystals are analysed for various physical properties by X-ray diffraction (XRD), Raman Spectroscopy, Scanning Electron Microscopy (SEM) coupled with Energy Dispersive X-ray Spectroscopy (EDAX) and electrical measurements under magnetic field (6Tesla) down to low temperature (2.5K). The XRD pattern revealed the growth of synthesized Sb 2 Te 3 sample along (00l) plane, whereas the SEM along with EDAX measurements displayed the layered structure with near stoichiometric composition, without foreign contamination. The Raman scattering studies displayed known (A 1g 1 , E g 2 and A 1g 2 ) vibrational modes for the studied Sb 2 Te 3 . The temperature dependent electrical resistivity measurements illustrated the metallic nature of the as grown Sb 2 Te 3 single crystal. Further, the magnetotransport studies represented linear positive magneto-resistance (MR) reaching up to 80% at 2.5K under an applied field of 6Tesla.The weak anti localization (WAL) related low field (± 2Tesla) magneto-conductance at low temperatures (2.5K and 20K) has been analysed and discussed using the Hikami-Larkin -Nagaoka (HLN) model. Summarily, the short letter reports an easy and versatile method for crystal growth of bulk Sb 2 Te 3 topological insulator (TI) and its brief physical property characterization.

We report crystal growth and below 2.5K superconductivity of Nb 0.25 Bi 2 Se 3 . These crystals are grown by self flux method. The X-ray diffraction (XRD) pattern of as grown crystal flake shows (00l) plane (c-orientation) growth. The Rietveld refinement of crushed crystal powder XRD (PXRD) pattern confirms the phase purity of the studied sample having R-3m space group of rhombohedral crystalline structure. The Raman spectrum of the studied Nb 0.25 Bi 2 Se 3 crystal distinctly shows three well defined vibrational modes in terms of A 1 1g , Eg 2 , A 2 1g at around 72, 129 and 173cm -1 , which are slightly shifted in comparison to pure Bi 2 Se 3 . Magnetization studies in terms of field cooled (FC) and Zero field cooled (ZFC) magnetic susceptibility measurements show the diamagnetic transition (T c onset ) of the compound at around 2.5K and near saturation of the same below around 2.1K. The isothernal magnetization (MH) being taken at 2K, revealed the lower critical field (H c1 ) of around 50Oe and the upper critical field (H c2 ) of 900Oe. It is clear the studied Nb 0.25 Bi 2 Se 3 is a bulk superconductor. The superconducting critical parameters thus calculated viz. the coherence length, upper and lower critical fields and superconducting transition temperature for as grown Nb 0.25 Bi 2 Se 3 single crystal are reported here.

We study the structural and bulk superconducting properties of self flux grown PdBi 2 Te 3 single crystal. Phase purity of as grown crystal is confirmed by Rietveld refinement of gently crushed powder XRD of the same. PdBi 2 Te 3 crystallizes in rhombohedral structure with R-3 m space group along with small impurity of Bi. Scanning Electron Microscopy (SEM) images showed layered structure and the elemental analysis by energy dispersive X Ray analysis (EDAX) done on same confirmed the stoichiometry to be near to PdBi 2 Te 3 . Characteristic vibrational modes viz. A 1 1g , Eg 2 , A 2 1g are clearly observed in Raman spectrum, and are slightly shifted from that as in case of Bi 2 Te 3 . Bulk superconductivity is confirmed by FC and ZFC magnetization measurements (M-T) exhibiting diamagnetic transition with T c onset at around 6K. M-H plots at different temperatures of 2K, 2.5K, 3K, 3.5K, 4K, 4.5K, 5K and 6K showed clear opening of the loop right up to 6K. Both M-T and M-H clearly establish the appearance of bulk type II superconductivity below 6K in studied PdBi 2 Te 3 . The lower critical field H c1 and upper critical field H c2 are at 180Oe at 4800Oe respectively at 2K for as grown PdBi 2 Te 3 crystal. Other critical parameters of superconductivity such as coherence length, penetration depth and kappa parameter are also calculated.