Ultrafast Spectroscopy of Bi2Se3 Topological Insulator

TL;DR

This study explores the ultrafast absorption properties of Bi2Se3 topological insulator crystals, revealing their structural characteristics, nonlinear optical behavior, and potential for Terahertz radiation generation.

Contribution

It provides detailed structural analysis and demonstrates the nonlinear optical response and THz generation capability of Bi2Se3 single crystals.

Findings

Crystallized in rhombohedral structure with specific lattice parameters.

Exhibits layered morphology with high crystallinity.

Capable of generating Terahertz radiation.

Abstract

We investigate the ultrafast transient absorption spectrum of Bi2Se3 topological insulator. Bi2Se3 single crystal is grown through conventional solid-state reaction routevia self-flux method. The structural properties have been studied in terms of high-resolution Powder X-ray Diffraction (PXRD). Detailed Rietveld analysis of PXRD of the crystal showed that sample is crystallized in the rhombohedral crystal structure with a space group of R-3m, and the lattice parameters are a=b=4.14A and c=28.7010A. Scanning Electron Microscopy (SEM) result shows perfectly crystalline structure with layered type morphology which evidenced from surface XRD. Energy Dispersive Spectroscopy (EDS) analysis determined quantitative amounts of the constituent atoms, found to be very close to their stoichiometric ratio. Further the fluence dependent nonlinear behaviour is studied by means of ultrafast transient absorption spectroscopy. The ultrafast spectroscopy also predicts the capability of this single crystal to generate Terahertz (THz) radiations (T-rays).