Surface characterization and magneto-transport study on Bi${}_2$Te${}_2$Se topological insulator thin film

Topological insulators (TIs) a new quantum state of matter predicted to have an interesting surface properties. In this report, we study the surface properties of Bi${}_2$Te${}_2$Se (BTS) topological insulators thin films. Raman measurements on BTS thin film show a strong intensity of A${}^1$${}_{1g}$ (∼62 cm${}^{\text{â}\text{ˆ}\text{’}1}$), E${}^2$${}_g$ (∼123 cm${}^{\text{â}\text{ˆ}\text{’}1}$) and A${}^2$${}_{1g}$ (∼170 cm${}^{\text{â}\text{ˆ}\text{’}1}$) modes in addition to A${}^2$${}_{1u}$ (∼140 cm${}^{\text{â}\text{ˆ}\text{’}1}$) modes. Elemental analyses were done using X-ray photoelectron spectroscopy (XPS). Resistance versus temperature measurement reveal a magnetic field-driven metallic behavior at high temperatures and further analysis on magnetic measurement shows a diamagnetic nature of BTS film. The magneto-resistance measurements on these films exhibit a weak antilocalization effect that arises due to quantum interfering nature of topological insulators and the measured weak anti-localization effect is fitted using Hikami–Larkin–Nagaoka (HLN) model.