Localization length and impurity dielectric susceptibility in the critical regime of the metal-insulator transition in homogeneously doped p-type Ge
- Department of Applied Physics and Physico-Informatics, Keio University, Yokohama 223-8522, (Japan)
- Institute of Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571, (Japan)
- Lawrence Berkeley National Laboratory and University of California at Berkeley, Berkeley, California 94720 (United States)
We have determined the localization length {xi} and the impurity dielectric susceptibility {chi}{sub imp} as a function of Ga acceptor concentrations (N) in nominally uncompensated {sup 70}Ge:Ga just below the critical concentration (N{sub c}) for the metal-insulator transition. Both {xi} and {chi}{sub imp} diverge at N{sub c} according to the functions {xi}{proportional_to}(1-N/N{sub c}){sup -{nu}} and {chi}{sub imp}{proportional_to}(N{sub c}/N-1){sup -{zeta}}, respectively, with {nu}=1.2{+-}0.3 and {zeta}=2.3{+-}0.6 for 0.99N{sub c}<N<N{sub c}. Outside of this region (N<0.99N{sub c}), the values of the exponents drop to {nu}=0.33{+-}0.03 and {zeta}=0.62{+-}0.05. The effect of the small amount of compensating dopants that are present in our nominally uncompensated samples, may be responsible for the change of the critical exponents at N{approx_equal}0.99N{sub c}. (c) 2000 The American Physical Society.
- OSTI ID:
- 20217217
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Journal Name: Physical Review. B, Condensed Matter and Materials Physics Journal Issue: 4 Vol. 62; ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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