2012/01/31 by P. Di Pietro, Paola Di Pietro, Francesco Vitucci +10 · 104 citations
Materials Science · Physics and Astronomy · #2D Materials and Applications #Bismuth #Charge carrier #Condensed matter physics #Conductivity #Graphene research and applications #Infrared #Materials science #Optical conductivity #Optics #Optoelectronics #Physics #Quantum mechanics #Spectral line #Terahertz radiation #Topological Materials and Phenomena #Topological insulator #cond-mat.mtrl-sci #cond-mat.other
paper · pdf · doi:10.1103/physrevb.86.045439
published in Physical Review B 86(4) (American Physical Society) · 5 pages, 4 figures
openalex publication_date 2012/07/24 · arxiv created 2012/09/12 · arxiv updated 2012/09/13 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The optical conductivity \ensuremathσ1(\ensuremathω) and the spectral weight SW of four topological insulators with increasing chemical compensation (Bi2Se3,\phantom\rule0.28em0exBi2Se2Te,\phantom\rule0.28em0exBi_2\ensuremath-xCaxSe3, and Bi2Te2Se) have been measured from 5 to 300 K and from subterahertz 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 SW of the most compensated sample (Bi2Te2Se), one can estimate a density of charge carriers on the order of 1017/cm3 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 influenced by three-dimensional charge excitations.