Quantitative evaluation of electron-electron-interaction effects in the magnetoconductivity of heavily doped metallic Si:P

The low-temperature correction {δ}{σ}=m {}T (m0) due to electron-electron interactions, to the electrical conductivity {σ} of metallic Si:P (with a P concentration 28% and 41% above the critical value Nc for the metal-insulator transition) is strongly modified when a magnetic field with gμBB>kBT is applied: {σ} decreases, and the slope mB of {δ}{σ} vs {}T becomes positive. The magnetoconductivity for T=const varies as {δ}{σ}=mR {}B with mR0. The three experimental values m, mB, and mR yield consistent values of the electron-electron-interaction parameter F̃ \~_σ when many-valley and anisotropy effects are taken into account, under the assumption that the valley degeneracy is lifted by the magnetic field. F̃ \~_σ is found to increase slightly from 1.17 to 1.40 in a magnetic field.