Stress-tuned metal-insulator transition in Si:B: dynamical scaling

S. Bogdanovich, M. P. Sarachik, Ravindra N. Bhatt

Research output: Contribution to journalConference article

3 Scopus citations

Abstract

Uniaxial stress S was used to tune the critical density of barely metallic Si:B at low temperatures through the metal-insulator transition. For all values of stress and temperature, the DC conductivity exhibits an excellent fit to the scaling form σ(S,T) = ATμ/zv f[(S - Sc)/T1/zv] on both sides of the transition. Finite temperature scaling yields a critical conductivity exponent μ = 1.6, considerably larger than the value obtained in experiments where the transition was crossed by varying the dopant concentration. Direct comparison of the temperature dependence of stressed and unstressed Si:B suggests that the stress-driven and concentration-driven metal-insulator transitions are not equivalent. We show that the conductivity in the critical region on the metallic side follows σc ∝ T 1/2 , the form that has been calculated and observed in the perturbative region for weakly disordered metals. The conductivity in the insulating phase follows the Efros-Shklovskii form, σ(S,T) ∝ exp([-(S - Sc)zv/T] 1/2 ), expected for variable-range hopping in the presence of Coulomb interactions, with a prefactor ∝ T 1/2 corresponding to the temperature dependence of the critical curve.

Original languageEnglish (US)
Pages (from-to)639-647
Number of pages9
JournalAnnalen der Physik (Leipzig)
Volume8
Issue number7
DOIs
StatePublished - Dec 1 1999
EventProceedings of the LOCALIZATION 1999 International Conference on 'Disorder and Interaction in Transport Phenomena' - Hamburg, Ger
Duration: Jul 29 1999Aug 3 1999

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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