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Scaling analysis of the low temperature conductivity in neutron‐transmutation‐doped 70 Ge:Ga
Author(s) -
Itoh K.M.,
Watanabe M.,
Ootuka Y.,
Haller E.E.
Publication year - 1999
Publication title -
annalen der physik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.009
H-Index - 68
eISSN - 1521-3889
pISSN - 0003-3804
DOI - 10.1002/(sici)1521-3889(199911)8:7/9<631::aid-andp631>3.0.co;2-6
Subject(s) - scaling , conductivity , critical exponent , exponent , condensed matter physics , physics , thermal conductivity , doping , neutron , nuclear transmutation , materials science , thermodynamics , nuclear physics , phase transition , linguistics , philosophy , geometry , mathematics , quantum mechanics
We report on the scaling analysis of low temperature electron transport properties of nominally uncompensated neutron‐transmutation‐doped 70 Ge:Ga samples in the critical regime for the metal‐insulator transition. Ga concentration ( N ) and temperature ( T ) dependent conductivities σ ( N , T ) are shown to collapse onto a single universal curve using finite temperature scaling of a form σ ( N , T ) ∝ T x f (| N / N c — 1|/ T y ) with x ≈ 0.38 and y ≈ 0.32 for the very small region of N = N c ± 0.004 N c . The conductivity critical exponent μ = x / y = 1.2 ± 0.2 found from this analysis is significantly larger than μ ≈ 0.5 found from the analysis we performed previously on the same series of samples covering the much larger region of the concentration N c < N < 1.4 N c . Determination of the true critical region, either N = N c ± 0.4% or N = N c ± 40%, is necessary in the future for the reliable determination of μ in Ge:Ga.