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New Approach for Determination of the Critical Behavior of Conductivity near the Metal–Insulator Transition in Doped Semiconductors
Author(s) -
Shlimak I.
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<287::aid-pssb287>3.0.co;2-c
Subject(s) - condensed matter physics , conductivity , scaling , impurity , materials science , doping , metal–insulator transition , coulomb , delocalized electron , critical exponent , exponent , electrical resistivity and conductivity , metal , semiconductor , electron , chemistry , physics , phase transition , quantum mechanics , metallurgy , linguistics , geometry , mathematics , philosophy , optoelectronics
Three peculiarities of the metal–insulator transition in the vicinity of the critical impurity concentration N c are discussed: (i) The temperature dependences of conductivity σ( T ) for barely metallic samples are almost parallel. This allows to suggest a new method for determining at non‐zero temperatures the value of the critical exponent μ in the scaling behavior of σ(0). It is shown that μ = 1 for different impurities in Ge and Si. (ii) The temperature‐independent conductivity at N > N c is proposed to be considered as the Mott minimal metallic conductivity σ M . It is shown that σ M normalizes the scaling behavior of σ(0) for various impurities. (iii) The temperature‐induced delocalization at T > T d is observed for barely insulating samples. The values of T d are normalized by the mean energy of the Coulomb interaction.