Hopping Conduction and Metal-Insulator Transition in Isotopically Enriched Neutron-Transmutation-Doped {sup 70}Ge:Ga
- Department of Applied Physics and Physico-Informatics, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223 (Japan)
We report on the electrical conductivity {sigma} of a series of nominally uncompensated neutron-transmutation-doped isotopically enriched {sup 70}Ge:Ga samples with the Ga concentration [Ga] near {ital N}{sub {ital c}} for the metal-insulator transition. {sigma} of all insulating samples obeys ln{sigma}{proportional_to}{minus}({ital T}{sub 0}/{ital T}){sup 1/2} with {ital T}{sub 0}{proportional_to}({ital N}{sub {ital c}}{minus}[Ga])/{ital N}{sub {ital c}} while the zero temperature conductivity {sigma}(0) of the metallic samples is {sigma}(0){proportional_to}{l_brace}([Ga]{minus}{ital N}{sub {ital c}})/{ital N}{sub {ital c}}{r_brace}{sup {nu}} with the critical exponent {nu}{approx_equal}0.5. The values of {ital N}{sub {ital c}} obtained from the two independent scalings of {ital T}{sub 0} and {sigma}(0) are identical, i.e., {nu}{approx_equal}0.5 is established unambiguously for uncompensated Ge:Ga. {copyright} {ital 1996 The American Physical Society.}
- Research Organization:
- Lawrence Berkeley National Laboratory
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 389398
- Journal Information:
- Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 19 Vol. 77; ISSN 0031-9007; ISSN PRLTAO
- Country of Publication:
- United States
- Language:
- English
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