Optical conductivity of Bismuth-based topological insulator

Abstract

The optical conductivity and the spectral weight of four topological insulators with increasing chemical compensation (Bi2Se3, Bi2-xCaxSe3, Bi2Se2Te, Bi2Te2Se) have been measured from 5 to 300 K and from sub-THz to visible frequencies. The effect of compensation is clearly observed in the infrared spectra, through the suppression of an extrinsic Drude term and the appearance of strong absorption peaks, that we assign to electronic transitions among localized states. From the far-infrared spectral weight of the most compensated sample (Bi2Te2Se) one can estimate a density of charge-carriers in the order of 10^17/cm^3 in good agreement with transport data. Those results demonstrate that the low-energy electrodynamics in single crystals of topological insulators, even at the highest degree of compensation presently achieved, is still affected by extrinsic charge excitations.

5 pages, 4 figures

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• Topological insulators are tunable waveguides for hyperbolic polaritons
• Evidence of surface transport and weak anti-localization in single crystal of Bi2Te2Se topological insulator
• Optical evidence of surface state suppression in Bi based topological insulators
• Revealing puddles of electrons and holes in compensated topological insulators
• Anisotropic longitudinal optical conductivities of tilted Dirac bands in 1T${}^{\prime }$-MoS${}_2$
• Propagation of Surface Plasmon Polaritons in Thin Films of Topological Insulators
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• Bi2Te_xSe_y series studied by resistivity and thermopower
• Optical properties of magnetically doped ultra-thin topological insulator slabs
• Interband absorption edge in topological insulators Bi${}_2$(Te${}_{1-x}$Se${}_x$)${}_3$
• Photocurrents in Bi2Se3: bulk versus surface, and injection versus shift currents
• Infrared electrodynamics and ferromagnetism in the topological semiconductors Bi${}_2$Te${}_3$ and Mn-doped Bi${}_2$Te${}_3$
• Faraday rotation due to surface states in the topological insulator (Bi${}_{1-x}$Sb${}_x$)${}_2$Te${}_3$
• Signatures of Lifshitz transition in the optical conductivity of two-dimensional tilted Dirac materials
• Van Hove Singularity Arising from Mexican-Hat-Shaped Inverted Bands in the Topological Insulator Sn-doped Bi${}_{1.1}$Sb${}_{0.9}$Te${}_2$S
• Optical responses and optical activity of ultrathin films of topological insulator
• Doping-dependent charge dynamics in CuxBi2Se3
• Optical investigation of thermoelectric topological crystalline insulator Pb${}_{0.77}$Sn${}_{0.23}$Se
• Bulk Fermi surface and electronic properties of Cu${}_{0.07}$Bi${}_2$Se${}_3$
• Charge-stripe Fluctuations in Nd${}_4$Ni${}_3$O${}_8$ as Evidenced by Optical Spectroscopy
• Strong light-matter interaction in systems described by a modified Dirac equation
• Topological cutoff frequency in a slab waveguide: Penetration length in topological insulator walls
• Thermoelectric and optical probes for a Fermi surface topology change in noncentrosymmetric metals
• Measurement of the topological surface state optical conductance in bulk-insulating Sn-doped Bi${}_{1.1}$Sb${}_{0.9}$Te${}_2$S single crystals
• Magneto-Infrared Spectroscopic Study of Ultrathin Bi${}_2$Te${}_3$ Single Crystals
• Electronic and Vibrational Excitations on the Surface of the Three-Dimensional Topological Insulator Bi${}_2$Te${}_{3-x}$Se${}_x$ (x = 0, 2, 3)
• Observation of optical absorption correlated with surface state of topological insulator
• Dynamical polarization and plasmons in noncentrosymmetric metals
• Direct Detection of Axion-Like Particles in Bismuth-Based Topological Insulators
• A DFT based first-principles investigation of the physical properties of Bi2Te2Se topological insulator