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Optical and Electrical Investigations of the Anisotropy of Sb 2 Te 3 Single Crystals
Author(s) -
Langhammer H. T.,
Stordeur M.,
Sobotta H.,
Riede V.
Publication year - 1982
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221090226
Subject(s) - anisotropy , condensed matter physics , materials science , electrical resistivity and conductivity , scattering , doping , conductivity , reflection (computer programming) , light scattering , optics , chemistry , physics , quantum mechanics , computer science , programming language
On Sb 2 Te 3 single crystals with conductivities between 3700 and 7000 Ω −1 cm −1 the anisotropy of the reflectivity of polarized infrared light, the anisotropy of conductivity and of the Seebeck and Hall coefficients are investigated. In addition to the excitation of free carriers in the reflection spectra of donor doped crystals also interband excitations are observed. In terms of a six‐valley band model with anisotropic scattering the contribution of the free carriers to the susceptibility is calculated, and the anisotropy ratio of the effective susceptibility massesis given. It is found that the anisotropy decreases with increasing conductivity. A comparison ofwith the anisotropy of conductivity σ ⊥c/σ‖c shows that for Sb 2 Te 3 single crystals with σ‖σ ⊥c < < 5000 Ω −1 cm −1 the carrier scattering is anisotropic.