Flux free single crystal growth and detailed physical property characterization of Bi1−xSbx (x = 0.05, 0.1 and 0.15) topological insulator

Abstract

Here, we report the crystal growth, physical and transport properties of Bi1−xSbx (x = 0.05, 0.1 and 0.15) topological insulator. Single crystals of Bi1-xSbx (x = 0.05, 0.1 and 0.15) were grown by melting bismuth and antimony together using the facile self flux method. The XRD measurements displayed highly indexed 00l lines and confirmed the crystalline nature as well as the rhombohedral structure of the Bi1-xSbx (x = 0.05, 0.1 and 0.15) crystals. Raman spectroscopy measurements for Bi1-xSbx system revealed four peaks within the spectral range of 10 to 250 cm−1 namely A1g and Eg modes corresponding to Bi-Bi and Sb-Sb vibrations. Scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDAX) measurements showed the layered surface morphology and near stoichiometric chemical composition of Bi1-xSbx (x = 0.05, 0.1 and 0.15) crystals. Furthermore, EDAX mapping confirmed the homogeneous distribution of Bi and Sb elements. Temperature dependent electrical resistivity curves with and without applied magnetic field exhibited a metallic behaviour and linear non-saturating magneto-resistance (MR) respectively for all the antimony (Sb) concentrations of x = 0.05, 0.1 and 0.15. The lowest Sb concentration sample with x = 0.05 (Bi0.95Sb0.05) exhibited the highest MR value of about 1400%, followed by x = 0.1 and 0.15 samples (Bi0.9Sb0.1 and Bi0.85Sb0.05) with MR values reaching up to 500% and 110% respectively at 2 K and 6Tesla applied field. Also, a coexistence of negative MR and WAL/WL behaviour is observed at lower magnetic fields (below ±0.2Tesla) in Bi0.9Sb0.1 and Bi0.85Sb0.05 system. To further elaborate the transport properties of Bi1-xSbx (x = 0.05, 0.1 and 0.15), the magneto-conductivity (MC) is fitted to the HLN (Hikami Larkin Nagaoka) equation and it is found that the charge conduction mechanism is mainly dominated by WAL (weak anti-localization) along with a small contribution from WL (weak localization) effect. Summarily, the short letter discusses the synthesis, interesting transport and magneto-transport properties of Bi1-xSbx (x = 0.05, 0.1 and 0.15), which could be useful in understanding the fascinating properties of topological insulators and their technological applications.