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Galvanomagnetic Properties of Bi 2 Se 3 with Free Carrier Densities below 5 × 10 17 cm −3
Author(s) -
Köhler H.,
Fabbicius A.
Publication year - 1975
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.2220710209
Subject(s) - condensed matter physics , magnetoresistance , impurity , saturation (graph theory) , magnetic field , atmospheric temperature range , hall effect , thermal conduction , free carrier , scattering , stoichiometry , electrical resistivity and conductivity , materials science , phonon , chemistry , physics , thermodynamics , combinatorics , optics , composite material , mathematics , organic chemistry , quantum mechanics
Bi 2 Se 3 , Bi 2 Te 3 , and Sb 2 Te 3 tend to grow non‐stoichiometric, the defects causing high free carrier densities. Here it was achieved, in the case of Bi 2 Se 3 , to produce crystals of n‐and p‐type conductivity showing concentrations down to 4 × 10 16 cm −3 . The temperature and magnetic field dependences of their galvanomagnetic properties are investigated. At low magnetic fields and low temperatures negative magnetoresistance occurs, at high magnetic fields no saturation of the positive magnetoresistance is observed which is assumed to originate from the influence of an impurity conduction band. The temperature dependence of the Hall constant enables the evaluation of the energy gap for thermal excitations to (160 ± 10) meV for T 0. The temperature dependence of the mobility between about 50 and 200 K supports the assumption of dominating scattering of the free carriers by acoustical phonons in this temperature range.