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Quantum Interference and Spin Effects in the Variable Range Hopping Magnetoresistance of Heavily Doped Semiconductors: Comparison between Si, Ge, CdTe and GaAs
Author(s) -
Rentzsch R.,
Ionov A. N.,
Reich Ch.,
Sandow B.,
Stefanyi P.,
Fozooni P.,
Lea M. J.
Publication year - 1998
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/(sici)1521-3951(199801)205:1<173::aid-pssb173>3.0.co;2-#
Subject(s) - variable range hopping , condensed matter physics , magnetoresistance , cadmium telluride photovoltaics , doping , semiconductor , quantum interference , spin (aerodynamics) , magnetic semiconductor , interference (communication) , materials science , range (aeronautics) , physics , optoelectronics , superconductivity , quantum mechanics , magnetic field , telecommunications , thermal conduction , computer science , composite material , thermodynamics , channel (broadcasting)
Abstract The negative hopping magnetoresistance (NHM) due to quantum interference, as well as the positive hopping magnetoresistance (PHM) due to the reduced overlap between the impurity wave functions should both only increase as the temperature decreases. For the first time in GaAs, CdTe and Ge we observed with decreasing temperatures a more complicated dependence on temperature and magnetic field. The NHM initially increases with decreasing temperature but then decreases sharply, and disappears at the lowest temperature. We relate this effect to the spin alignment of the impurity atoms in the magnetic field for g μ* B ≫ k B T . Experimentally this new spin contribution depends strongly on the impurity concentration which, together with the critical concentration of the MIT, increases in the sequence of GaAs, CdTe, Ge, Si from 2×10 16 to 3.5×10 18 cm —3 . The small NHM in Ge and its absence in Si may be due to dominating spin effects.