Growth, Characterization and High-Field Magneto-Conductivity of Co0.1Bi2Se3 Topological Insulator

Abstract

We report the crystal growth as well as transport properties of Co added Bi2Se3 (Co0.1Bi2Se3) single crystals. The values of the lattice parameters for pure and Co added sample were nearly the same. The Raman spectroscopy displayed slightly higher Raman shift of corresponding A1g1, Eg2, and A1g2 vibrational modes for Co0.1Bi2Se3, and the resistivity curves with and without applied magnetic field show a metallic behavior. Both the crystals were subjected to magneto-resistance (MR) measurements under applied fields of 14 T. The value of MR is found to decrease from about 380% (5 K, 14 T) for Bi2Se3 to 200% for Co0.1Bi2Se3. To elaborate the transport properties of pure and Co added Bi2Se3 crystals, the magneto-conductivity is fitted to the HLN (Hikami-Larkin-Nagaoka) equation, and it is found that the charge conduction is mainly dominated by surface-driven WAL (weak anti-localization) with negligible bulk WL (weak localization) contribution in both crystals alike. The MH curves of Co0.1Bi2Se3 crystal at different temperatures displayed a combination of both ferromagnetic and diamagnetic behavior. On the other hand, the electron paramagnetic resonance (EPR) revealed that pure Bi2Se3 is diamagnetic, whereas Co orders ferromagnetically with resonating field around 3422 Oe at room temperature. The calculated value of Lande “g” factor is around 2.04 ± 0.05. Summarily, the short letter discusses the interesting magneto-conductivity and complex magnetism of Co in Co0.1Bi2Se3.