Universal scaling of the magnetoconductance of metallic Si:B.

Abstract

Conductivity data for Si:B samples with dopant concentrations 1.01 ${n}_{c}<n<{1.22n}_{c}$ at temperatures between 0.07 and 0.5 K in magnetic fields from 0 to 9.0 T collapse onto a single universal curve $\ensuremath{\Delta}\ensuremath{\sigma}{\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}KT}^{1/2}F(H/T)$, the form expected for the magnetoconductance due to electron-electron interactions. This suggests that the metal-insulator transition is predominantly driven by electron correlations, and that localization, spin-flip scattering, and spin-orbit scattering are unimportant despite strong spin-orbit effects in Si:B.